High-level ab initio study of LiO (X-2 Pi; A(2)Sigma(+)) and LiO+ (X-3 Sigma(-) ; A(3)Pi): the ionization energy of LiO

摘要

RCCSD(T) calculations are performed using basis sets of quadruple- and quintuple-zeta quality. Potential energy curves are calculated for the lowest two neutral states of LiO (X(2)Pi and A(2)Sigma (+)), as well as the lowest two triplet states of LiO+ (X(3)Sigma (-) and A(3)Pi). From these curves spectroscopic parameters are calculated, including anharmonic vibrational frequencies and rotational constants. For the X(2)Pi state, excellent agreement with microwave and infrared values is obtained. The I separation is calculated to be 2419 cm(-1), and the first adiabatic ionization energy (AIE) corresponding to the process X(3)Sigma (-) <-- X(2)Pi is calculated to be 8.55 +/- 0.05 eV. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 32]