Spectroscopic Parameter and Molecular Constant Investigations on Low-Lying States of BeF Radical

摘要

The potential energy curves (PECs) of X2∑+, A2Π_r and B2∑+ states of BeF radical have been investigated using the complete active space self-consistent-field (CASSCF) method, followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach at the correlation-consistent basis sets, cc-pV5Z for Be and aug-cc-pV6Z for F. Based on the PECs of X2∑+, A2Π_r and B2∑+ states, the spectroscopic parameters (D_e, R_e, ω_e, ω_eχ_e, α_e and B_e) have also been determined in the present work. With the PECs determined at the present level of theory, vibrational states have been predicted for each state when the rotational quantum number J equals zero (J = 0). The vibrational levels, inertial rotation and centrifugal distortion constants are determined for the three states, and the classical turning points are also calculated for the X2∑+ state. Compared with the available experiments and other theories, it can be seen that the present spectroscopic parameter and molecular constant results are more fully in agreement with the experimental findings.