Spectroscopic constants and potential energy curves of 47 electronic states of InSb, InSb+, and InSb−

Abstract

Spectroscopic constants and potential energy curves of 26 electronic states of InSb, 12 electronic states of InSb+, and 9 electronic states of InSb− are obtained using complete active space self-consistent field, first-order configuration interaction, second-order configuration interaction, and relativistic configuration interaction methods (CASSCF/FOCI/SOCI/RCI), including spin–orbit interaction. The SOCI calculations included up to 700 000 configurations. Spectroscopic constants obtained predict several allowed electronic transitions for InSb, InSb+, and InSb− which are yet to be observed. The ground states of InSb, InSb+, and InSb− are found to be X 3Σ−0+, X 4Σ−1/2, and X 2Σ+1/2 with the constants InSb X 3Σ−0+:Re =3.02 Å, ωe =121 cm−1, De =1.35 eV; X 3Σ−1 : Re =3.03 Å, ωe =136 cm−1, Te =494 cm−1; InSb+ X 4Σ−1/2 : Re =3.351 Å, ωe =63 cm−1, De =0.37 eV; and InSb− X 2Π3/2 : Re =2.695 Å, ωe =191 cm−1, De =2.5 eV. The adiabatic ionization potential and electron affinity of InSb are calculated as 6.33 and 1.41 eV, respectively. Analogous to the recently observed A 3Π–X3Σ− system of GaAs, spectral bands in the 20 200 cm−1 region are predicted for InSb. Another 3Π(II)–X3Σ− system is predicted at 15 830 cm−1. Both the 3Π states in these systems are found to be predissociated through crossing of a repulsive 5Σ− curve. The two low-lying electronic states of InSb− (2Σ+1/2, 2Π1/2) undergo relativistic avoided crossing.