Theoretical investigations on the SH+(X3Σ−) ion using coupled-cluster theory in combination with the correlation-consistent quintuple basis set augmented with diffuse functions

Abstract

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 SH+( X3Σ−) ion. The accurate potential energy curve is calculated over the internuclear separation range from 0.09 to 2.46 nm and is fitted to the analytic Murrell-Sorbie function, which is used to accurately determine the spectroscopic parameters such as De, ωeχe, αe, and Be. The present De, Re, ωe, ωeχe, αe, and Be values are 3.69119 eV, 0.13644 nm, 2,556.429 cm−1, 49.290 cm−1, 0.289 cm−1, and 9.2677 cm−1, respectively, which are in excellent agreement with the available measurements. With the potential obtained at the UCCSD( T)/aug-cc-pV5Z level of theory, a total of 21 vibrational states is predicted when J = 0 by numerically solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation, and centrifugal distortion constants are reproduced from the potential energy curve of the SH+( X3Σ−) ion when J = 0 for the first time. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009