The Experts below are selected from a list of 717507 Experts worldwide ranked by ideXlab platform
Steven G Louie - One of the best experts on this subject based on the ideXlab platform.
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wigner crystallization in the fractional quantum hall regime a variational quantum monte carlo study
Physical Review Letters, 1993Co-Authors: Steven G LouieAbstract:Using a variational quantum Monte Carlo method, we study the two-dimensional Wigner crystal induced by a strong magnetic field in the fractional quantum Hall effect regime. Effects of exchange, intra-Landau-Level Correlation, and inter-Landau-Level mixing on the total energy and their dependence on the carrier mass and magnetic field strength are calculated. Our results support that the recently observed reentrant behavior to an insulating phase around [nu]=1/3 in [ital p]-doped GaAs/AlGaAs is a consequence of an increased stability of the Wigner crystal due to the effects of Landau-Level mixing.
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wigner crystallization in the fractional quantum hall regime a variational quantum monte carlo study
Physical Review Letters, 1993Co-Authors: Steven G Louie, Xuejun ZhuAbstract:Using a variational quantum Monte Carlo method, we study the two-dimensional Wigner crystal induced by a strong magnetic field in the fractional quantum Hall effect regime. Effects of exchange, intra-Landau-Level Correlation, and inter-Landau-Level mixing on the total energy and their dependence on the carrier mass and magnetic field strength are calculated. Our results support that the recently observed reentrant behavior to an insulating phase around \ensuremath{\nu}=1/3 in p-doped GaAs/AlGaAs is a consequence of an increased stability of the Wigner crystal due to the effects of Landau-Level mixing.
John A. Pople - One of the best experts on this subject based on the ideXlab platform.
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yiel...
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yields significantly better agreement with experiment for several cases including the ionization potentials of CS and O2, electron affinity of CN, and dissociation energies of N2, O2, CN, and SO2. This leads to a slightly better agreement with experiment overall. The MP2 zero‐point energies gives no overall improvement. These methods may be useful for specific systems.
Larry A. Curtiss - One of the best experts on this subject based on the ideXlab platform.
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yiel...
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yields significantly better agreement with experiment for several cases including the ionization potentials of CS and O2, electron affinity of CN, and dissociation energies of N2, O2, CN, and SO2. This leads to a slightly better agreement with experiment overall. The MP2 zero‐point energies gives no overall improvement. These methods may be useful for specific systems.
Krishnan Raghavachari - One of the best experts on this subject based on the ideXlab platform.
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yiel...
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gaussian 2 theory use of higher Level Correlation methods quadratic configuration interaction geometries and second order mo ller plesset zero point energies
Journal of Chemical Physics, 1995Co-Authors: Larry A. Curtiss, Krishnan Raghavachari, John A. PopleAbstract:The performance of Gaussian‐2 theory is investigated when higher Level theoretical methods are included for Correlation effects, geometries, and zero‐point energies. A higher Level of Correlation treatment is examined using Brueckner doubles [BD(T)] and coupled cluster [CCSD(T)] methods rather than quadratic configuration interaction [QCISD(T)]. The use of geometries optimized at the QCISD Level rather than the second‐order Mo/ller–Plesset Level (MP2) and the use of scaled MP2 zero‐point energies rather than scaled Hartree–Fock (HF) zero‐point energies have also been examined. The set of 125 energies used for validation of G2 theory [J. Chem. Phys. 94, 7221 (1991)] is used to test out these variations of G2 theory. Inclusion of higher Levels of Correlation treatment has little effect except in the cases of multiply‐bonded systems. In these cases better agreement is obtained in some cases and poorer agreement in others so that there is no improvement in overall performance. The use of QCISD geometries yields significantly better agreement with experiment for several cases including the ionization potentials of CS and O2, electron affinity of CN, and dissociation energies of N2, O2, CN, and SO2. This leads to a slightly better agreement with experiment overall. The MP2 zero‐point energies gives no overall improvement. These methods may be useful for specific systems.
Xuejun Zhu - One of the best experts on this subject based on the ideXlab platform.
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wigner crystallization in the fractional quantum hall regime a variational quantum monte carlo study
Physical Review Letters, 1993Co-Authors: Steven G Louie, Xuejun ZhuAbstract:Using a variational quantum Monte Carlo method, we study the two-dimensional Wigner crystal induced by a strong magnetic field in the fractional quantum Hall effect regime. Effects of exchange, intra-Landau-Level Correlation, and inter-Landau-Level mixing on the total energy and their dependence on the carrier mass and magnetic field strength are calculated. Our results support that the recently observed reentrant behavior to an insulating phase around \ensuremath{\nu}=1/3 in p-doped GaAs/AlGaAs is a consequence of an increased stability of the Wigner crystal due to the effects of Landau-Level mixing.