Ground and Excited State Properties of ThB- and ThB: A Theoretical Study

Abstract

In the present work, we studied a series of electronic and spin-orbit states of ThB– and ThB at high-level multireference and coupled-cluster levels of theory. We report potential energy curves (PECs), equilibrium electron configurations, spectroscopic constants, energetics, and spin-orbit coupling effects of 17 and 19 electronic states of ThB– and ThB, respectively. The ground state of ThB– is a single-reference 13Π with 1σ22σ23σ11π3 electron configuration. Detachment of an electron from the 1π2 of ThB–(13Π) produces the single-reference ground electronic state of ThB (14Σ-). The ground spin-orbit states of ThB– and of ThB are 13Π_(0^+ ) and 14Σ-3/2, respectively. The vertical electron detachment energy (VDE) of ThB– and the adiabatic electron attachment energy (AEA) of ThB at our largest CCSD(T)+δT(Q)+δSO (spin-orbit effects and triple and perturbative quadruple electron correlation effects added coupled-cluster theory with single, double, and perturbative triple excitations) level are 1.473 eV and 1.459, respectively. The reaction of Th(3F) + B(2Po) produces the ground state of ThB with a dissociation energy (D0) of 2.897 eV. Finally, we estimated a heat of formation, 〖ΔH〗_f^o (298 K), of 885.80 kJ/mol for the ThB molecule. The high-level findings of this work are expected to aid and motivate future experimental spectroscopic investigations of ThB and ThB– species.