Spectroscopic investigations on HBr+(X2Π) ion using CCSD(T) theory in combination with cc-pV5Z basis set

Abstract

The equilibrium internuclear separations, harmonic frequencies, and potential energy curves (PECs) of the HBr+(X2Π) ion have been investigated using the coupled-cluster singles-doubles-approximate-triples [CCSD(T)] theory in combination with the series of correlation-consistent basis sets in the valence range. The PECs are all fitted to the Murrell-Sorbie function, which are used to reproduce the spectroscopic parameters such as De, ωeχe, αe, Be, and D0. The present D0, De, Re, ωe, ωeχe, αe, and Be obtained at the cc-pV5Z basis set are of 3.9730 eV, 4.1243 eV, 0.14427 nm, 2462.970 cm−1, 47.6979 cm−1, 0.2361 cm−1, and 8.13591 cm−1, respectively, which almost perfectly conform to the measurements. With the potential obtained at the UCCSD(T)/cc-pV5Z level of theory, a total of 22 vibrational states is predicted when the rotational quantum number J is set to equal zero (J = 0) by numerically solving the radial Schrodinger equation of nuclear motion. The complete vibrational levels and their corresponding classical turning points, inertial rotation, and centrifugal distortion constants are determined when J = 0 for the first time, which are in excellent agreement with the available experiments. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011