A theoretical study of low‐lying electronic states of aminonitrene, phosphinonitrene, and phosphinocarbene

Autor: Mark R. Hoffmann, Kathleen M. Kuhler
Rok vydání: 1991
Předmět:
Zdroj: The Journal of Chemical Physics. 94:8029-8039
ISSN: 1089-7690
0021-9606
DOI: 10.1063/1.460137
Popis: The recently formulated multiconfiguration‐based unitary coupled electron pair approximation (UCEPA) is compared with multireference configuration interaction (MR‐CISD) calculations, including all single and double excitations, for the molecules in this study. The electronic states of the molecules in this study are not only of experimental interest, but represent a challenge to any formalism to accurately predict the energy separations of the low‐lying electronic states. The equilibrium geometries and fundamental vibrational frequencies of the three lowest electronic states (i.e., 1A1, 3A‘, and 1A‘) of aminonitrene H2N2, and phosphinonitrene, H2PN, have been determined using a split‐valence basis with polarization functions on the heavy atoms and a small complete active space self‐consistent‐field (CASSCF) description of the active space. Both MR‐CISD and UCEPA calculations have been performed at the equilibrium structures using larger basis sets to accurately determine the relative energetics of the ele...
Databáze: OpenAIRE