A theoretical investigation of the excited states of OCLO radical, cation, and anion using the CASSCF/CASPT2 method

Abstract

Using the complete active space self-consistent field method with a large atomic natural orbital basis set, 10, 13, and 9 electronic states of the OClO radical, OClO(+) cation, and OClO(-) anion were calculated, respectively. Taking the further correlation effects into account, the second-order perturbation (CASPT2) calculations were carried out for the energetic calibration. The photoelectron spectroscopy of the OClO radical and OClO(-) anion were extensively studied in the both case of the adiabatic and vertical ionization energies. The calculated results presented the relatively complete assignment of the photoelectron bands of the experiments for OClO and its anion. Furthermore, the Rydberg states of the OClO radical were investigated by using multiconfigurational CASPT2 (MS-CASPT2) theory under the basis set of large atomic natural orbital functions augmented with an adapted 1s1p1d Rydberg functions that have specially been built for this study. Sixteen Rydberg states were obtained and the results were consistent with the experimental results.

Electronic excitation spectra of radical anions of cyanoethylenes and cyanobenzenes: Symmetry adapted cluster–configuration interaction study

“…28 Since then, of course, remarkable progress in theory and computational technique for spectral analysis has been made. Among many others, [29][30][31][32][33][34][35][36] CASSCF and CASPT2 studies have been performed recently for several anionic species. 22,30,31,[34][35][36] But, even with recent advances in quantum chemistry theory, it is not easy to calculate dependable electronic excited states of radical anions compared with calculations for the closed-shell neutral molecules.…”

DEA dynamics of chlorine dioxide probed by velocity slice imaging

“…The theoretical calculations by Baluja et al 15 found no anion state in this energy range whereas Wei et al 16 reported a pair of B1 states in the energy range of 1 to 2 eV with an equilibrium bond length close to that of the neutral ground state. However, in this state they have found the equilibrium bond angle to be smaller indicating effective bending excitations from the Frank-Condon transition.…”

“…The resonance obtained in these calculations around 3 eV is a single particle shape resonance of B1 symmetry. Wei et al 16 have reported an anion excited state near 1.5 eV with the smaller bond angle (112 0 ) and similar bond length as that of neutral ground state. Our results on OCl  validate this assignment.…”

“…They reported the OClO  anion ground state (X 1 A1) to be 1.558 eV below the OClO ground state and found several shape resonances of 3 B1, 1 B1, 3 A2, and 1 A2 symmetries at 2.96 eV, 5.75 eV, 7.22 eV and 8.06 eV with widths of 0.843 eV, 1.4 eV, 1.5 eV and 2.72 eV respectively. Wei et al 16 have reported the excited anion states in the energy range of 0 to 3 eV from neutral ground state by performing quantum chemical calculations using a complete active space self-consistent field method with a large atomic natural orbital basis set.…”

Single-Sheeted Double Many-Body Expansion Potential Energy Surface for Ground-State ClO2

“…Grant et al 36 have included the OClO and ClOO species in a detailed ab initio investigation of the thermodynamic properties of halogen oxides based on coupled cluster theory and the correlated consistent basis sets of Dunning, obtaining accurate results for properties such as total atomization energies, geometries, frequencies, heats of formation, and bond dissociation energies. Additionally, Wei et al 37 have reported an extensive ab initio study of the spectroscopic properties of several excited states of the OClO radical as well as of its anion and cation, employing CASPT2/CASSCF methods with a large atomic natural orbital (ANO-L) basis set. They have given equilibrium structures, ionization potentials, detachment energies, and absorption spectra of up to 10, 13, and 9 electronic states of OClO, OClO + , and OClO − , respectively.…”