The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Yongqin Wei - One of the best experts on this subject based on the ideXlab platform.
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hyper Polarizabilities and optical absorption spectra of msi12 clusters m sc zn a theoretical study
Chemical Physics Letters, 2010Co-Authors: Yongqin WeiAbstract:Abstract The dipole Polarizabilities, second-order hyperPolarizabilities, and optical absorption spectra of MSi 12 clusters (M = Sc–Zn) have been studied by using the (time-dependent) density functional theory. The results demonstrate that the correlation functional exerts more remarkable influence on the dipole polarizability and second-order hyperpolarizability calculations than the exchange term. Referring to MP2 results, B3LYP provides poorer dipole Polarizabilities but more reliable second-order hyperPolarizabilities than B3PW91 and mPW1PW91 functionals. Additionally, the tunable (hyper)Polarizabilities and optical absorption spectra have been evidently observed, which are attributed to the strong hybridization between 3d orbitals of M and 3s, 3p states of Si.
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(Hyper)Polarizabilities and optical absorption spectra of MSi12 clusters (M = Sc–Zn): A theoretical study
Chemical Physics Letters, 2010Co-Authors: Yongqin WeiAbstract:Abstract The dipole Polarizabilities, second-order hyperPolarizabilities, and optical absorption spectra of MSi 12 clusters (M = Sc–Zn) have been studied by using the (time-dependent) density functional theory. The results demonstrate that the correlation functional exerts more remarkable influence on the dipole polarizability and second-order hyperpolarizability calculations than the exchange term. Referring to MP2 results, B3LYP provides poorer dipole Polarizabilities but more reliable second-order hyperPolarizabilities than B3PW91 and mPW1PW91 functionals. Additionally, the tunable (hyper)Polarizabilities and optical absorption spectra have been evidently observed, which are attributed to the strong hybridization between 3d orbitals of M and 3s, 3p states of Si.
Jim Mitroy - One of the best experts on this subject based on the ideXlab platform.
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effective oscillator strength distributions of spherically symmetric atoms for calculating Polarizabilities and long range atom atom interactions
arXiv: Atomic Physics, 2014Co-Authors: Jim Mitroy, Yong Jun Cheng, Jun Jiang, Michael W J BromleyAbstract:Effective oscillator strength distributions are systematically generated and tabulated for the alkali atoms, the alkaline-earth atoms, the alkaline-earth ions, the rare gases and some miscellaneous atoms. These effective distributions are used to compute the dipole, quadrupole and octupole static Polarizabilities, and are then applied to the calculation of the dynamic Polarizabilities at imaginary frequencies. These Polarizabilities can be used to determine the long-range $C_6$, $C_8$ and $C_{10}$ atom-atom interactions for the dimers formed from any of these atoms and ions, and we present tables covering all of these combinations.
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Blackbody radiation shift of the Ga+ clock transition
Journal of Physics B: Atomic Molecular and Optical Physics, 2013Co-Authors: Yong Jun Cheng, Jim MitroyAbstract:The blackbody radiation shift of the Ga+ clock transition is computed to be ?0.0140 ? 0.0062 Hz at 300?K. The small shift is consistent with the blackbody radiation shifts of the clock transitions of other group III ions which are of a similar size. The Polarizabilities of the Ga+ , , and states were computed using the configuration interaction method with an underlying semi-empirical core potential. Quadrupole and non-adiabatic dipole Polarizabilities were also computed. A byproduct of the analysis involved calculations of the low-lying spectrum and oscillator strengths, including Polarizabilities, of the Ga2 + ion.
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Blackbody radiation shift of the B + clock transition
Physical Review A, 2012Co-Authors: Yong Jun Cheng, Jim MitroyAbstract:A calculation of the blackbody radiation shift of the B+ clock transition is performed. The Polarizabilities of the B+2s2 1Se, 2s2p 1Po, and 2s2p 3Po states are computed using the configuration interaction method with an underlying semiempirical core potential. The recommended dipole Polarizabilities are 9.64(3)a03, 7.78(3)a03 and 16.55(5)a03, respectively. The derived frequency shift for the 2s2 1Se → 2s2p 3P0o transition at 300 K is 0.0160(5) Hz. The dipole Polarizabilities agree with an earlier relativistic calculation [Safronova et al., Phys. Rev. Lett. 107, 143006 (2011)] to better than 0.2%. Quadrupole and octupole Polarizabilities and nonadiabatic multipole Polarizabilities are also reported.
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multipole Polarizabilities and long range interactions of the fluorine atom
Journal of Chemical Physics, 2009Co-Authors: Oleg Zatsarinny, Jim Mitroy, Klaus Bartschat, Junyi ZhangAbstract:The Polarizabilities of the ground state of fluorine are determined by the box-based B-spline configuration-interaction method. The ground-state static and tensor Polarizabilities are calculated as αd=3.49a03 and α2=0.303a03, respectively. The resulting excitation matrix elements are employed to compute the interatomic dispersion interactions for the HF and F2 molecules.
Tunna Baruah - One of the best experts on this subject based on the ideXlab platform.
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study of self interaction errors in density functional predictions of dipole Polarizabilities and ionization energies of water clusters using perdew zunger and locally scaled self interaction corrected methods
Journal of Chemical Physics, 2020Co-Authors: Sharmin Akter, Yoh Yamamoto, Carlos Diaz, Koblar A Jackson, Rajendra R Zope, Tunna BaruahAbstract:We studied the effect of self-interaction error (SIE) on the static dipole Polarizabilities of water clusters modeled with three increasingly sophisticated, non-empirical density functional approximations (DFAs), viz., the local spin density approximation (LDA), the Perdew–Burke–Ernzerhof (PBE) generalized-gradient approximation (GGA), and the strongly constrained and appropriately normed (SCAN) meta-GGA, using the Perdew–Zunger self-interaction-correction (PZ-SIC) energy functional in the Fermi–Lowdin orbital SIC framework. Our results show that while all three DFAs overestimate the cluster Polarizabilities, the description systematically improves from LDA to PBE to SCAN. The self-correlation free SCAN predicts Polarizabilities quite accurately with a mean absolute error (MAE) of 0.53 bohr3 with respect to coupled cluster singles and doubles (CCSD) values. Removing SIE using PZ-SIC correctly reduces the DFA Polarizabilities, but overcorrects, resulting in underestimated Polarizabilities in SIC-LDA, SIC-PBE, and SIC-SCAN. Finally, we applied a recently proposed locally scaled SIC (LSIC) method using a quasi self-consistent scheme and using the kinetic energy density ratio as an iso-orbital indicator. The results show that the LSIC Polarizabilities are in excellent agreement with mean absolute errors of 0.08 bohr3 for LSIC-LDA and 0.06 bohr3 for LSIC-PBE with most recent CCSD Polarizabilities. Likewise, the ionization energy estimates as absolute of highest occupied energy eigenvalue predicted by LSIC are also in excellent agreement with CCSD(T) ionization energies with MAEs of 0.4 eV for LSIC-LDA and 0.06 eV for LSIC-PBE. The LSIC-LDA predictions of ionization energies are comparable to the reported GW ionization energies, while the LSIC-PBE ionization energies are more accurate than the reported GW results.
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study of self interaction errors in density functional predictions of dipole Polarizabilities and ionization energies of water clusters using perdew zunger and locally scaled self interaction corrected methods
arXiv: Chemical Physics, 2020Co-Authors: Sharmin Akter, Yoh Yamamoto, Carlos Diaz, Koblar A Jackson, Rajendra R Zope, Tunna BaruahAbstract:We studied the effect of self-interaction error (SIE) on the static dipole Polarizabilities of water clusters modelled with three increasingly sophisticated, non-empirical density functional approximations (DFAs), viz. the local spin density approximation (LDA), the Perdew-Burke-Ernzherof (PBE) generalized-gradient approximation (GGA), and the strongly constrained and appropriately normed (SCAN) meta-GGA, using the Perdew-Zunger self-interaction-correction (PZ-SIC) energy functional in the Fermi-L\"owdin orbital SIC (FLO-SIC) framework. Our results show that while all three DFAs overestimate the cluster Polarizabilities, the description systematically improves from LDA to PBE to SCAN. The self-correlation free SCAN predicts Polarizabilities quite accurately with a mean absolute error (MAE) of 0.58 Bohr$^3$ with respect to coupled cluster singles and doubles (CCSD) values. Removing SIE using PZ-SIC correctly reduces the DFA Polarizabilities, but over-corrects, resulting in underestimated Polarizabilities in SIC-LDA, -PBE, and -SCAN. Finally, we applied a recently proposed local-scaling SIC (LSIC) method using a quasi self-consistent scheme and using the kinetic energy density ratio as an iso-orbital indicator. The results show that the LSIC Polarizabilities are in excellent agreement with mean absolute error of 0.08 Bohr$^3$ for LSIC-LDA and 0.06 Bohr$^3$ for LSIC-PBE with most recent CCSD Polarizabilities. Likewise, the ionization energy estimates as an absolute of highest occupied energy eigenvalue predicted by LSIC are also in excellent agreement with CCSD(T) ionization energies with MAE of 0.4 eV for LSIC-LDA and 0.04 eV for LSIC-PBE. The LSIC-LDA predictions of ionization energies are comparable to the reported GW ionization energies while the LSIC-PBE ionization energies are more accurate than reported GW results.
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self interaction free electric dipole Polarizabilities for atoms and their ions using the fermi lowdin self interaction correction
Physical Review A, 2019Co-Authors: Kushantha Withanage, Sharmin Akter, Yoh Yamamoto, Carlos Diaz, Rajendra R Zope, Tunna Baruah, Chandra Shahi, Rajendra P Joshi, John P Perdew, Juan E PeraltaAbstract:The static electric dipole polarizability of a system is a measure of the binding of its electrons. In density functional theory calculations, this binding is weakened by the presence of unphysical self-interaction in the density functional approximation (DFA), leading to overestimates of Polarizabilities. To investigate this systematically we compare Polarizabilities for the atoms from H to Ar and their anions and cations calculated in several DFAs and the corresponding self-interaction-corrected (SIC) DFAs with experiment and with high-level quantum chemistry reference values. The SIC results are obtained using the Fermi-L\"owdin orbital self-interaction correction (FLO-SIC) method. Removing self-interaction generally leads to smaller Polarizabilities that agree significantly better with reference values. We find that FLO-SIC improves the performance of the local spin density approximation and the generalized gradient approximation (GGA) for Polarizabilities to a quality that is comparable to so-called rung 4 functionals, but slightly degrades the performance of the strongly constrained and appropriately normed meta-GGA functional.
Andrei Derevianko - One of the best experts on this subject based on the ideXlab platform.
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Dipole Polarizabilities of excited alkali-metal atoms and long-range interactions of ground- and excited-state alkali-metal atoms with helium atoms
Physical Review A, 2004Co-Authors: C. Zhu, Sergey G. Porsev, Alexander Dalgarno, Andrei DereviankoAbstract:The scalar and tensor dynamic Polarizabilities of the first excited P1/2,3/2 states of the alkali-metal atoms Na, K, and Rb are calculated using relativistic many-body perturbation theory. Comparison with experimental measurements of the static Polarizabilities suggests that the errors in the theoretical predictions do not exceed 1%. The dynamic Polarizabilities at imaginary frequencies are employed to calculate the long-range van der Waals coefficients for the interaction of ground-state helium atoms with the excited alkali-metal atoms to a probable error of less than 2%.
Yong Jun Cheng - One of the best experts on this subject based on the ideXlab platform.
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effective oscillator strength distributions of spherically symmetric atoms for calculating Polarizabilities and long range atom atom interactions
arXiv: Atomic Physics, 2014Co-Authors: Jim Mitroy, Yong Jun Cheng, Jun Jiang, Michael W J BromleyAbstract:Effective oscillator strength distributions are systematically generated and tabulated for the alkali atoms, the alkaline-earth atoms, the alkaline-earth ions, the rare gases and some miscellaneous atoms. These effective distributions are used to compute the dipole, quadrupole and octupole static Polarizabilities, and are then applied to the calculation of the dynamic Polarizabilities at imaginary frequencies. These Polarizabilities can be used to determine the long-range $C_6$, $C_8$ and $C_{10}$ atom-atom interactions for the dimers formed from any of these atoms and ions, and we present tables covering all of these combinations.
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Blackbody radiation shift of the Ga+ clock transition
Journal of Physics B: Atomic Molecular and Optical Physics, 2013Co-Authors: Yong Jun Cheng, Jim MitroyAbstract:The blackbody radiation shift of the Ga+ clock transition is computed to be ?0.0140 ? 0.0062 Hz at 300?K. The small shift is consistent with the blackbody radiation shifts of the clock transitions of other group III ions which are of a similar size. The Polarizabilities of the Ga+ , , and states were computed using the configuration interaction method with an underlying semi-empirical core potential. Quadrupole and non-adiabatic dipole Polarizabilities were also computed. A byproduct of the analysis involved calculations of the low-lying spectrum and oscillator strengths, including Polarizabilities, of the Ga2 + ion.
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Blackbody radiation shift of the B + clock transition
Physical Review A, 2012Co-Authors: Yong Jun Cheng, Jim MitroyAbstract:A calculation of the blackbody radiation shift of the B+ clock transition is performed. The Polarizabilities of the B+2s2 1Se, 2s2p 1Po, and 2s2p 3Po states are computed using the configuration interaction method with an underlying semiempirical core potential. The recommended dipole Polarizabilities are 9.64(3)a03, 7.78(3)a03 and 16.55(5)a03, respectively. The derived frequency shift for the 2s2 1Se → 2s2p 3P0o transition at 300 K is 0.0160(5) Hz. The dipole Polarizabilities agree with an earlier relativistic calculation [Safronova et al., Phys. Rev. Lett. 107, 143006 (2011)] to better than 0.2%. Quadrupole and octupole Polarizabilities and nonadiabatic multipole Polarizabilities are also reported.
