Analytic First-Order Derivatives of (X)MS, XDW, and RMS Variants of the CASPT2 and RASPT2 Methods.
J Chem Theory Comput
; 18(7): 4269-4281, 2022 Jul 12.
Article
em En
| MEDLINE
| ID: mdl-35699280
ABSTRACT
Crossings between states involve complex electronic structures, making the accurate characterization of the crossing point difficult. In this study, the analytic derivatives of three complete active space second-order perturbation theory (CASPT2) variants as well as an extension of the restricted active space (RASPT2) are developed. These variants are applied to locating minimum energy conical intersections. Our results demonstrate that the three CASPT2 variants predict qualitatively similar results, but a recently developed variant, the rotated multistate CASPT2 (RMS-CASPT2), is least sensitive to the number of states considered in the calculation. We demonstrate that CASPT2 and the reference self-consistent field calculations predict qualitatively different energetics and bond lengths.
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Base de dados:
MEDLINE
Assunto principal:
Teoria Quântica
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article