Investigations on Spectroscopic Properties of ND(X-3 Sigma(-)) Radical Using Coupled-Cluster Theory in Combination With the Correlation-Consistent Quintuple Basis Set Augmented With Diffuse Functions

摘要

The coupled-cluster singles-doubles-approximate-triples [CCSD(T)] theory in combination with the correlation-consistent quintuple basis set augmented with diffuse functions (aug-cc-pV5Z) is used to investigate the spectroscopic properties of the ND(X-3 Sigma(-)) radical. The adiabatic potential energy curve is calculated over the internuclear separation range from 0.06 to 2.47 nm and fitted to the analytic Murrell-Sorbie function, which is used to determine the spectroscopic parameters, omega(e)chi(e), alpha(e), and B-e. The present D-e, R-e, omega(e), omega(e)chi(e), alpha(e), and B-e. values are of 3.57357 eV, 0.10367 nm, 2403.166 cm(-1), 42.888 cm(-1), 0.25344 cm(-1), and 8.90867 cm(-1), respectively, which are in excellent agreement with the available measurements. With the potential obtained at the UCCSD(T)/aug-cc-pVD5Z level of theory, a total of 21 vibrational states is predicted when J = 0 by numerically solving the radial Schrodinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation, and centrifugal distortion constants are reproduced for the ND(X-3 Sigma(-)) radical when J = 0 for the first time, which are in good accord with the available RKR data. (C) 2008 Wiley Periodicals, Inc. Int J Quantum Chem 109: 202-209, 2009