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  • 1.
    Jiemchooroj, Auayporn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    First-principles calculations of long-range intermolecular dispersion forces2006Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This work presents first-principles calculations of long-range intermolecular dispersion energies between two atoms or molecules as expressed in terms of the C6 dipole-dipole dispersion coefficients. In a series of publications, it has been shown by us that the complex linear polarization propagator method provides accurate ab initio and first-principles density functional theory values of the C6 dispersion coefficients in comparison with those reported in the literature. The selected samples for the investigation of dispersion interactions in the electronic ground state are the noble gases, n-alkanes, polyacenes, azabenzenes, and C60. It has been shown that the proposed method can also be used to determine dispersion energies for species in their respective excited electronic states. The C6 dispersion coefficients for the first ππ* excited state of the azabenzene molecules have been obtained with the adopted method in the multiconfiguration self-consistent field approximation. The dispersion energy of the ππ* excited state is smaller r than that of the ground state. It is found that the characteristic frequencies ω1 defined in the London approximation of n-alkanes vary in a narrow range and that makes it possible to construct a simple structure-to-property relation based on the number of -bonds for the dispersion interaction in these saturated compounds. However, this simple approach is not applicable for the interactions of the π-conjugated systems since their characteristic frequencies ω1 vary strongly depending on the systems.

    Delarbeten
    1. Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes
    Öppna denna publikation i ny flik eller fönster >>Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes
    2003 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 118, nr 20, s. 9167-9174Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The linear polarization propagator has been computed at imaginary frequencies for He, Ne, Ar, and Kr as well as for the n-alkanes including heptane and its smaller members. It is shown that an effective and direct evaluation of the polarization propagator using standard electronic structure first principle methods can be achieved on the whole imaginary axis without expanding the polarizability in a series of the Cauchy moments. The linear response equation will be complex in this case, but an effective algorithm can be constructed so that the computational cost parallels that of the real propagator. Calculations of the polarizability tensor are used to determine the Casimir–Polder interaction potentials for the molecules under consideration. Theoretical results for the C6 dispersion coefficient are compared with accurate experimental data, and it is shown that results for the extended n-alkanes obtained with density functional theory and the hybrid B3LYP exchange correlation functional are in excellent agreement with experiment. At the same level of theory, on the other hand, there are significant discrepancies for the noble gas atoms. The electron correlation contribution to C6 is less than 9% for the n-alkanes and decreases with the size of the system.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14047 (URN)10.1063/1.1568082 (DOI)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
    2. C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure
    Öppna denna publikation i ny flik eller fönster >>C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure
    2004 (Engelska)Ingår i: Physical Review A, ISSN 1050-2947, Vol. 69, nr 44701, s. 44701-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We report on calculations of the dipole-dipole dispersion coefficients for pairs of n -alkane molecules. The results are based on first-principles calculations of the molecular polarizabilities with a purely imaginary frequency argument and which were reported by us in a previous work [P. Norman, A. Jiemchooroj, and Bo E. Sernelius, J. Chem. Phys. 118, 9167 (2003)]. The results for the static polarizabilities and dispersion coefficients are compared to simple algebraic expressions in terms of the number of CC and CH bonds in the two weakly interacting species. The bond additivity procedure is shown to perform well in the present case, and bond polarizabilities of 4.256 and 3.964  a.u . are proposed for the CH and the CC bond, respectively.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14048 (URN)10.1103/PhysRevA.69.044701 (DOI)
    Anmärkning
    Original Publication: Auayporn Jiemchooroj, Bo E. Sernelius and Patrick Norman, C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure, 2004, Physical Review A, (69), 44701, 44701. http://dx.doi.org/10.1103/PhysRevA.69.044701 Copyright: American Physical Society http://www.aps.org/ Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
    3. First principle calculations of dipole-dipole dispersion coefficients for the ground and first pi π → π* excited states of some azabenzenes
    Öppna denna publikation i ny flik eller fönster >>First principle calculations of dipole-dipole dispersion coefficients for the ground and first pi π → π* excited states of some azabenzenes
    2004 (Engelska)Ingår i: Journal of Computational Methods in Science and Engineering, ISSN 1472-7978, Vol. 4, nr 3, s. 321-332Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The complex polarization propagator method has been applied to the calculation of dipole-dipole dispersion coefficients (also known as C_6 coefficients) of pyridine, pyrazine, and s-tetrazine. These calculations refer to the electronic ground states as well as the first excited states of π → π* character. It is argued that accurate ground state dispersion coefficients are obtained with density functional theory using the B3LYP exchange-correlation functional. The proposed values for the C_6 coefficients of pyridine, pyrazine, and s-tetrazine in their ground states are 1543 a.u., 1398 a.u., and 1014 a.u., respectively. Multi-configurational complete active space calculations are performed on these compounds in their respective π → π* excited state. The isotropic averages of the frequency-dependent polarizabilities are smaller in the excited states, but the effective frequencies - defined in the London - van der Waals dispersion relation - are on the other hand larger.

    Ort, förlag, år, upplaga, sidor
    I O S Press, 2004
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14049 (URN)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2018-05-24
    4. Complex polarization propagator method for calculation of dispersion coefficients of extended π-conjugated systems: The C6 coefficients of polyacenes and C60
    Öppna denna publikation i ny flik eller fönster >>Complex polarization propagator method for calculation of dispersion coefficients of extended π-conjugated systems: The C6 coefficients of polyacenes and C60
    2005 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 123, nr 12, s. 124312-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The frequency-dependent polarizabilities and the C6 dipole-dipole dispersion coefficients for the first members of the polyacenes namely benzene, naphthalene, anthracene, and naphthacene as well as the fullerene C60 have been calculated at the time-dependent Hartree-Fock level and the time-dependent density-functional theory level with the hybrid B3LYP exchange-correlation functional. The dynamic polarizabilities at imaginary frequencies are obtained with use of the complex linear polarization propagator method and the C6 coefficients are subsequently determined from the Casimir-Polder relation. We report the first ab initio calculations of the C6 coefficients for the molecules under consideration, and our recommended value for the dispersion coefficient of the fullerene is 101.0  a.u.

    Nyckelord
    organic compounds, fullerenes, atomic clusters, polarisability, HF calculations, density functional theory, ab initio calculations
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14050 (URN)10.1063/1.2035589 (DOI)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
  • 2.
    Jiemchooroj, Auayporn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Long-range intermolecular dispersion forces and circular dichroism spectra from first-principles calculations2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This work presents first-principles calculations of long-range intermolecular dispersion energies between two atoms or molecules and of electronic circular dichroism spectra of chiral molecules. The former is expressed in terms of the C6 dipole-dipole dispersion coefficients Δε, and the latter is given in terms of the extinction coefficient. In a series of publications, the complex linear polarization propagator method has been shown to be a powerful tool to provide accurate ab initio and first-principles density functional theory results. This was the case not only for the C6 dispersion coefficients but also for the electronic circular dichroism at an arbitrary wavelength ranging from the optical to the X-ray regions of the spectrum. The selected samples for the investigation of dispersion interactions in the electronic ground state are the noble gases, n-alkanes, polyacenes, azabenzenes, alkali-metal clusters, and C60. It is found that the values of C6 for the sodium-cluster-to-fullerene interactions are well within the error bars of the experiment. The proposed method can also be used to determine dispersion energies for species in their respective excited electronic states. The C6 dispersion coefficients for the first π → π* excited state of the azabenzene molecules have been obtained with the adopted method in the multiconfiguration self-consistent field approximation. The dispersion energy of the π → π* excited state is smaller than that of the ground state. It is found that the characteristic frequencies ω1 defined in the London approximation of n-alkanes vary in a narrow range which makes it possible to construct a simple structure-to-property relationship based on the number of π-bonds for the dispersion interaction in these saturated compounds. However, this simple approach is not applicable to the interactions of the π-conjugated systems since, depending on the systems, their characteristic frequencies ω1 can vary greatly. In addition, an accomplishment of calculations of the electronic circular dichroism spectra in the near-edge X-ray absorption has been demonstrated.

    Delarbeten
    1. Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes
    Öppna denna publikation i ny flik eller fönster >>Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes
    2003 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 118, nr 20, s. 9167-9174Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The linear polarization propagator has been computed at imaginary frequencies for He, Ne, Ar, and Kr as well as for the n-alkanes including heptane and its smaller members. It is shown that an effective and direct evaluation of the polarization propagator using standard electronic structure first principle methods can be achieved on the whole imaginary axis without expanding the polarizability in a series of the Cauchy moments. The linear response equation will be complex in this case, but an effective algorithm can be constructed so that the computational cost parallels that of the real propagator. Calculations of the polarizability tensor are used to determine the Casimir–Polder interaction potentials for the molecules under consideration. Theoretical results for the C6 dispersion coefficient are compared with accurate experimental data, and it is shown that results for the extended n-alkanes obtained with density functional theory and the hybrid B3LYP exchange correlation functional are in excellent agreement with experiment. At the same level of theory, on the other hand, there are significant discrepancies for the noble gas atoms. The electron correlation contribution to C6 is less than 9% for the n-alkanes and decreases with the size of the system.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14047 (URN)10.1063/1.1568082 (DOI)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
    2. C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure
    Öppna denna publikation i ny flik eller fönster >>C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure
    2004 (Engelska)Ingår i: Physical Review A, ISSN 1050-2947, Vol. 69, nr 44701, s. 44701-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We report on calculations of the dipole-dipole dispersion coefficients for pairs of n -alkane molecules. The results are based on first-principles calculations of the molecular polarizabilities with a purely imaginary frequency argument and which were reported by us in a previous work [P. Norman, A. Jiemchooroj, and Bo E. Sernelius, J. Chem. Phys. 118, 9167 (2003)]. The results for the static polarizabilities and dispersion coefficients are compared to simple algebraic expressions in terms of the number of CC and CH bonds in the two weakly interacting species. The bond additivity procedure is shown to perform well in the present case, and bond polarizabilities of 4.256 and 3.964  a.u . are proposed for the CH and the CC bond, respectively.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14048 (URN)10.1103/PhysRevA.69.044701 (DOI)
    Anmärkning
    Original Publication: Auayporn Jiemchooroj, Bo E. Sernelius and Patrick Norman, C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure, 2004, Physical Review A, (69), 44701, 44701. http://dx.doi.org/10.1103/PhysRevA.69.044701 Copyright: American Physical Society http://www.aps.org/ Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
    3. First principle calculations of dipole-dipole dispersion coefficients for the ground and first pi π → π* excited states of some azabenzenes
    Öppna denna publikation i ny flik eller fönster >>First principle calculations of dipole-dipole dispersion coefficients for the ground and first pi π → π* excited states of some azabenzenes
    2004 (Engelska)Ingår i: Journal of Computational Methods in Science and Engineering, ISSN 1472-7978, Vol. 4, nr 3, s. 321-332Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The complex polarization propagator method has been applied to the calculation of dipole-dipole dispersion coefficients (also known as C_6 coefficients) of pyridine, pyrazine, and s-tetrazine. These calculations refer to the electronic ground states as well as the first excited states of π → π* character. It is argued that accurate ground state dispersion coefficients are obtained with density functional theory using the B3LYP exchange-correlation functional. The proposed values for the C_6 coefficients of pyridine, pyrazine, and s-tetrazine in their ground states are 1543 a.u., 1398 a.u., and 1014 a.u., respectively. Multi-configurational complete active space calculations are performed on these compounds in their respective π → π* excited state. The isotropic averages of the frequency-dependent polarizabilities are smaller in the excited states, but the effective frequencies - defined in the London - van der Waals dispersion relation - are on the other hand larger.

    Ort, förlag, år, upplaga, sidor
    I O S Press, 2004
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14049 (URN)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2018-05-24
    4. Complex polarization propagator method for calculation of dispersion coefficients of extended π-conjugated systems: The C6 coefficients of polyacenes and C60
    Öppna denna publikation i ny flik eller fönster >>Complex polarization propagator method for calculation of dispersion coefficients of extended π-conjugated systems: The C6 coefficients of polyacenes and C60
    2005 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 123, nr 12, s. 124312-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The frequency-dependent polarizabilities and the C6 dipole-dipole dispersion coefficients for the first members of the polyacenes namely benzene, naphthalene, anthracene, and naphthacene as well as the fullerene C60 have been calculated at the time-dependent Hartree-Fock level and the time-dependent density-functional theory level with the hybrid B3LYP exchange-correlation functional. The dynamic polarizabilities at imaginary frequencies are obtained with use of the complex linear polarization propagator method and the C6 coefficients are subsequently determined from the Casimir-Polder relation. We report the first ab initio calculations of the C6 coefficients for the molecules under consideration, and our recommended value for the dispersion coefficient of the fullerene is 101.0  a.u.

    Nyckelord
    organic compounds, fullerenes, atomic clusters, polarisability, HF calculations, density functional theory, ab initio calculations
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14050 (URN)10.1063/1.2035589 (DOI)
    Tillgänglig från: 2006-10-05 Skapad: 2006-10-05 Senast uppdaterad: 2013-10-02
    5. Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for sodium clusters and C60
    Öppna denna publikation i ny flik eller fönster >>Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for sodium clusters and C60
    2006 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 125, nr 12, s. 124306-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The frequency-dependent polarizabilities of closed-shell sodium clusters containing up to 20 atoms have been calculated using the linear complex polarization propagator approach in conjunction with Hartree-Fock and Kohn-Sham density functional theories. In combination with polarizabilities for C60 from a previous work [J. Chem. Phys. 123, 124312 (2005)], the C6 dipole-dipole dispersion coefficients for the metal-cluster-to-cluster and cluster-to-buckminster-fullerene interactions are obtained via the Casimir-Polder relation [Phys. Rev. 73, 360 (1948)]. The B3PW91 results for the polarizability of the sodium dimer and tetramer are benchmarked against coupled cluster calculations. The error bars of the reported theoretical results for the C6 coefficients are estimated to be 5%, and the results are well within the error bars of the experiment.

    Nyckelord
    sodium, fullerenes, atomic clusters, polarisability, HF calculations, density functional theory, coupled cluster calculations
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-12721 (URN)10.1063/1.2348882 (DOI)
    Anmärkning
    Original Publication: Auayporn Jiemchooroj, Patrick Norman and Bo. E. Sernelius, Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for sodium clusters and C60, 2006, Journal of Chemical Physics, (125), 12, 124306. http://dx.doi.org/10.1063/1.2348882 Copyright: American Institute of Physics http://www.aip.org/ Tillgänglig från: 2007-11-16 Skapad: 2007-11-16 Senast uppdaterad: 2013-10-02
    6. Electronic circular dichroism spectra from the complex polarization propagator
    Öppna denna publikation i ny flik eller fönster >>Electronic circular dichroism spectra from the complex polarization propagator
    2007 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 126, nr 13, s. 134102-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The complex linear polarization propagator approach has been applied to the calculation of electronic circular dichroism spectra of 3R-chloro-1-butyne, 3R-methylcyclopentanone, 3S-methylcyclohexanone, 4R-1,1-dimethyl-[3]-(1,2)ferrocenophan-2-on, S-3,3,3,3-tetramethyl-1,1-spirobi[3H,2,1]-benzoxaselenole, and the fullerene C84. Using time-dependent Kohn-Sham density functional theory, it is shown that a direct and efficient evaluation of the circular dichroism spectrum can be achieved. The approach allows for the determination of the circular dichroism at an arbitrary wavelength thereby, in a common formulation and implementation, covering the visible, ultraviolet, and x-ray regions of the spectrum. In contrast to traditional methods, the entire manifold of excited states is taken into account in the calculation of the circular dichroism at a given wavelength

    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:liu:diva-12722 (URN)10.1063/1.2716660 (DOI)
    Tillgänglig från: 2007-11-16 Skapad: 2007-11-16 Senast uppdaterad: 2017-12-14
    7. Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for alkali metal clusters and C60
    Öppna denna publikation i ny flik eller fönster >>Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for alkali metal clusters and C60
    2007 (Engelska)Ingår i: Journal of Computational Methods in Sciences and Engineering, ISSN 1472-7978, E-ISSN 1875-8983, Vol. 7, nr 5-6, s. 475-488Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The frequency dependent polarizabilities of closed-shell alkali metal clusters containing up to ten lithium, potassium, and rubidium atoms have been calculated using the linear complex polarization propagator approach in conjunction with Hartree – Fock and Kohn – Sham density functional theory. In combination with polarizabilities for C_{60} from a previous work [J. Chem. Phys. 123, 124312 (2005)], the C_6 dipole-dipole dispersion coefficients for the metal cluster-to-cluster and cluster-to-buckminster fullerene interactions are obtained via the Casimir – Polder relation. The B3PW91 results for the polarizabilities and dispersion interactions of the alkali metal dimers and tetramers are benchmarked against couple cluster calculations, and the whole series of calculations are compared against the corresponding work on sodium clusters [J. Chem. Phys. 125, 124306 (2006)]. The error bars of the reported theoretical results for the C_6 coefficients are estimated to be 8%.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-12723 (URN)
    Anmärkning
    Original Publication: Auayporn Jiemchooroj, Bo. E. Sernelius and Patrick Norman, Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for alkali metal clusters and C60, 2007, Journal of Computational Methods in Sciences and Engineering, (7), 5-6, 475-488. Copyright: IOS Press http://iospress.metapress.com/ Tillgänglig från: 2007-11-16 Skapad: 2007-11-16 Senast uppdaterad: 2017-12-14
    8. Near-edge X-ray absorption and natural circular dichroism spectra of L-alanine: a theoretical study based on the complex polarization propagator approach
    Öppna denna publikation i ny flik eller fönster >>Near-edge X-ray absorption and natural circular dichroism spectra of L-alanine: a theoretical study based on the complex polarization propagator approach
    2007 (Engelska)Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 127, nr 16, s. 165104-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The complex polarization propagator method [J. Chem. Phys. 123, 194103 (2005)] has been employed in conjunction with density functional theory and gauge-including atomic orbitals in order to determine the near-edge x-ray absorption and natural circular dichroism spectra of L-alanine in its neutral and zwitterionic forms. Results are presented for the K-edges of carbon, nitrogen, and oxygen. In contrast to traditional methods, the proposed approach enables a direct determination ofspectra at an arbitrary frequency instead of focusing on the rotatory strengths for individual electronic transitions. The propagator includes a complete set ofand allows for full core-hole relaxation. The theoretical spectrum at the nitrogen K-edge of the zwitterion compares well with the experimental spectrum. the nonredundant electron-transfer operators

    Nyckelord
    X-ray absorption near edge structure, absorption spectra, dichroism, polarization spectroscopy, density functionals, atomic orbitals
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-12724 (URN)10.1063/1.2800024 (DOI)
    Tillgänglig från: 2007-11-16 Skapad: 2007-11-16 Senast uppdaterad: 2017-12-14
  • 3.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Ekström, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Near-edge X-ray absorption and natural circular dichroism spectra of L-alanine: a theoretical study based on the complex polarization propagator approach2007Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 127, nr 16, s. 165104-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex polarization propagator method [J. Chem. Phys. 123, 194103 (2005)] has been employed in conjunction with density functional theory and gauge-including atomic orbitals in order to determine the near-edge x-ray absorption and natural circular dichroism spectra of L-alanine in its neutral and zwitterionic forms. Results are presented for the K-edges of carbon, nitrogen, and oxygen. In contrast to traditional methods, the proposed approach enables a direct determination ofspectra at an arbitrary frequency instead of focusing on the rotatory strengths for individual electronic transitions. The propagator includes a complete set ofand allows for full core-hole relaxation. The theoretical spectrum at the nitrogen K-edge of the zwitterion compares well with the experimental spectrum. the nonredundant electron-transfer operators

  • 4.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Electronic circular dichroism spectra from the complex polarization propagator2007Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 126, nr 13, s. 134102-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex linear polarization propagator approach has been applied to the calculation of electronic circular dichroism spectra of 3R-chloro-1-butyne, 3R-methylcyclopentanone, 3S-methylcyclohexanone, 4R-1,1-dimethyl-[3]-(1,2)ferrocenophan-2-on, S-3,3,3,3-tetramethyl-1,1-spirobi[3H,2,1]-benzoxaselenole, and the fullerene C84. Using time-dependent Kohn-Sham density functional theory, it is shown that a direct and efficient evaluation of the circular dichroism spectrum can be achieved. The approach allows for the determination of the circular dichroism at an arbitrary wavelength thereby, in a common formulation and implementation, covering the visible, ultraviolet, and x-ray regions of the spectrum. In contrast to traditional methods, the entire manifold of excited states is taken into account in the calculation of the circular dichroism at a given wavelength

  • 5.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Norman, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik.
    X-ray absorption and natural circular dichroism spectra of C84: A theoretical study using the complex polarization propagator approach2008Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 128, nr 23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The x-ray absorption and circular dichroism K -edge spectra for the D2 -isomer of C84 have been determined using the complex polarization propagator method in conjunction with Kohn-Sham density functional theory. The circular dichroism spectrum is rich in details and, in comparison to the absorption spectrum, it provides a superior resolution of the electronic transitions below the ionization threshold. © 2008 American Institute of Physics.

  • 6.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Complex polarization propagator method for calculation of dispersion coefficients of extended π-conjugated systems: The C6 coefficients of polyacenes and C602005Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 123, nr 12, s. 124312-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The frequency-dependent polarizabilities and the C6 dipole-dipole dispersion coefficients for the first members of the polyacenes namely benzene, naphthalene, anthracene, and naphthacene as well as the fullerene C60 have been calculated at the time-dependent Hartree-Fock level and the time-dependent density-functional theory level with the hybrid B3LYP exchange-correlation functional. The dynamic polarizabilities at imaginary frequencies are obtained with use of the complex linear polarization propagator method and the C6 coefficients are subsequently determined from the Casimir-Polder relation. We report the first ab initio calculations of the C6 coefficients for the molecules under consideration, and our recommended value for the dispersion coefficient of the fullerene is 101.0  a.u.

  • 7.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo. E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for sodium clusters and C602006Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 125, nr 12, s. 124306-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The frequency-dependent polarizabilities of closed-shell sodium clusters containing up to 20 atoms have been calculated using the linear complex polarization propagator approach in conjunction with Hartree-Fock and Kohn-Sham density functional theories. In combination with polarizabilities for C60 from a previous work [J. Chem. Phys. 123, 124312 (2005)], the C6 dipole-dipole dispersion coefficients for the metal-cluster-to-cluster and cluster-to-buckminster-fullerene interactions are obtained via the Casimir-Polder relation [Phys. Rev. 73, 360 (1948)]. The B3PW91 results for the polarizability of the sodium dimer and tetramer are benchmarked against coupled cluster calculations. The error bars of the reported theoretical results for the C6 coefficients are estimated to be 5%, and the results are well within the error bars of the experiment.

  • 8.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    C6 dipole-dipole dispersion coefficients for the n-alkanes: Test of an additivity procedure2004Ingår i: Physical Review A, ISSN 1050-2947, Vol. 69, nr 44701, s. 44701-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on calculations of the dipole-dipole dispersion coefficients for pairs of n -alkane molecules. The results are based on first-principles calculations of the molecular polarizabilities with a purely imaginary frequency argument and which were reported by us in a previous work [P. Norman, A. Jiemchooroj, and Bo E. Sernelius, J. Chem. Phys. 118, 9167 (2003)]. The results for the static polarizabilities and dispersion coefficients are compared to simple algebraic expressions in terms of the number of CC and CH bonds in the two weakly interacting species. The bond additivity procedure is shown to perform well in the present case, and bond polarizabilities of 4.256 and 3.964  a.u . are proposed for the CH and the CC bond, respectively.

  • 9.
    Jiemchooroj, Auayporn
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo. E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Norman, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Electric dipole polarizabilities and C6 dipole-dipole dispersion coefficients for alkali metal clusters and C602007Ingår i: Journal of Computational Methods in Sciences and Engineering, ISSN 1472-7978, E-ISSN 1875-8983, Vol. 7, nr 5-6, s. 475-488Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The frequency dependent polarizabilities of closed-shell alkali metal clusters containing up to ten lithium, potassium, and rubidium atoms have been calculated using the linear complex polarization propagator approach in conjunction with Hartree – Fock and Kohn – Sham density functional theory. In combination with polarizabilities for C_{60} from a previous work [J. Chem. Phys. 123, 124312 (2005)], the C_6 dipole-dipole dispersion coefficients for the metal cluster-to-cluster and cluster-to-buckminster fullerene interactions are obtained via the Casimir – Polder relation. The B3PW91 results for the polarizabilities and dispersion interactions of the alkali metal dimers and tetramers are benchmarked against couple cluster calculations, and the whole series of calculations are compared against the corresponding work on sodium clusters [J. Chem. Phys. 125, 124306 (2006)]. The error bars of the reported theoretical results for the C_6 coefficients are estimated to be 8%.

  • 10.
    Norman, Patrick
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Jiemchooroj, Auayporn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    First principle calculations of dipole-dipole dispersion coefficients for the ground and first pi π → π* excited states of some azabenzenes2004Ingår i: Journal of Computational Methods in Science and Engineering, ISSN 1472-7978, Vol. 4, nr 3, s. 321-332Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex polarization propagator method has been applied to the calculation of dipole-dipole dispersion coefficients (also known as C_6 coefficients) of pyridine, pyrazine, and s-tetrazine. These calculations refer to the electronic ground states as well as the first excited states of π → π* character. It is argued that accurate ground state dispersion coefficients are obtained with density functional theory using the B3LYP exchange-correlation functional. The proposed values for the C_6 coefficients of pyridine, pyrazine, and s-tetrazine in their ground states are 1543 a.u., 1398 a.u., and 1014 a.u., respectively. Multi-configurational complete active space calculations are performed on these compounds in their respective π → π* excited state. The isotropic averages of the frequency-dependent polarizabilities are smaller in the excited states, but the effective frequencies - defined in the London - van der Waals dispersion relation - are on the other hand larger.

  • 11.
    Norman, Patrick
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Beräkningsfysik. Linköpings universitet, Tekniska högskolan.
    Jiemchooroj, Auayporn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Sernelius, Bo E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes2003Ingår i: Journal of Chemical Physics, ISSN 0021-9606, Vol. 118, nr 20, s. 9167-9174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The linear polarization propagator has been computed at imaginary frequencies for He, Ne, Ar, and Kr as well as for the n-alkanes including heptane and its smaller members. It is shown that an effective and direct evaluation of the polarization propagator using standard electronic structure first principle methods can be achieved on the whole imaginary axis without expanding the polarizability in a series of the Cauchy moments. The linear response equation will be complex in this case, but an effective algorithm can be constructed so that the computational cost parallels that of the real propagator. Calculations of the polarizability tensor are used to determine the Casimir–Polder interaction potentials for the molecules under consideration. Theoretical results for the C6 dispersion coefficient are compared with accurate experimental data, and it is shown that results for the extended n-alkanes obtained with density functional theory and the hybrid B3LYP exchange correlation functional are in excellent agreement with experiment. At the same level of theory, on the other hand, there are significant discrepancies for the noble gas atoms. The electron correlation contribution to C6 is less than 9% for the n-alkanes and decreases with the size of the system.

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