Browsing by Author "Cimiraglia, Renzo"

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Multireference perturbation theory can predict a false ground state
(2010)
Camacho, Cristopher
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Cimiraglia, Renzo
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Witek, Henryk A.
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應用化學系
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應用化學系分子科學碩博班
Prediction of a false ground state with popular variants of multireference perturbation theory (CASPT2 and MRMP) is reported for a remarkably simple chemical system: the Sc(2) molecule.
Reply to the 'Comment on "Multiconfigurational perturbation theory can predict a false ground state"' by J. Soto, F. Avila, J. C. Otero and J. F. Arenas, Phys. Chem. Chem. Phys., 2011
(2011)
Camacho, Cristopher
;
Cimiraglia, Renzo
;
Witek, Henryk A.
;
應用化學系
;
應用化學系分子科學碩博班
The low-lying states of the scandium dimer
(2010-06-28)
Camacho, Cristopher
;
Witek, Henryk A.
;
Cimiraglia, Renzo
;
應用化學系
;
應用化學系分子科學碩博班
A systematic investigation of low-lying states of Sc(2) using multireference perturbation theory (NEVPT2 and NEVPT3) indicates that the ground state of this system is 5 Sigma(u) with r(e)= 2.611 angstrom, w(e)= 241.8 cm(-1), and De= 1.78 eV. This state is closely followed by other low-lying states of Sc(2): (3)Sigma(u)-, (5)Delta(u), (3)Pi(g), (1)Pi(g), and (1)Sigma(u)-. Our energy ordering of the (5)Sigma(u)- and (3)Sigma(u)- states confirms the recent MRCI results of Kalemos et al. [J. Chem. Phys. 132, 024309 (2010)] and is at variance with the earlier diffusion Monte Carlo predictions of Matxain et al. [J. Chem. Phys. 128, 194315 (2008)]. An excellent agreement between the second-and third-order NEVPT results and between the computed and experimental values of omega(e) (241.8 versus 238.9 cm(-1)) for the (5)Sigma(u)- state suggests high accuracy of our predictions. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3442374]