CCSD(T)‐F12 investigations on HBNH and its isotopologues

Abstract

CCSD(T)-F12 ab initio computations are performed to investigate the isomerization path between HBNH and BNH 2 , and the six-dimensional potential energy surface of the electronic ground state X 1 R þ of the linear isomer. The equilibrium geometries and harmonic wavenumbers obtained at the CCSD(T)-F12a/aug-cc-pVTZ level of theory are nearly those computed with the CCSD(T)/aug-cc-pV5Z level, but with a smaller amount of CPU time for the evaluation of the total energy. The analytical representation of the potential energy surface is used in variational calculations of the rovibrational energy levels of H 11 BNH and isotopologues. The computed rovibrational energy levels are compared with the available experimental data, and a good agreement is generally noticed. We also propose an assignment of the rovibrational energy levels of H 11 BNH up to 3000 cm À1 above the zero point energy.

Rovibrational energy levels of the F−(H2O) and F−(D2O) complexes

“…Explicitly correlated methods of electronic structure theory 24,25 appear to be a good compromise, as well demonstrated in the literature. [26][27][28] The ground electronic state PES of the F À (H 2 O) complex is computed here at the all-electron, explicitly correlated CCSD(T)-F12a level 24,25,29 of electronic structure theory; thus, the important effects of core-valence electron correlation 30 are fully taken into account.…”