Infrared Spectra and Theoretical Calculations of BSe₂ and BSe₂^–: The Pseudo-Jahn–Teller Effect

Abstract

Matrix isolation infrared spectroscopy has been employed to study the reaction of laser-ablated boron atoms with hydrogen selenide in a 5 K solid argon matrix. On the basis of the isotopic shifts as well as the theoretical frequency calculations, triatomic molecule BSe 2 and its anion BSe 2 − were identified. Both BSe 2 and BSe 2 − were predicted to have D ∞h symmetric structures with nearly identical structure parameters and bond strengths by quantum chemical calculations. Whereas the observed antisymmetric B−Se stretching frequency of BSe 2 is much lower than that of BSe 2 − , the anomalously low antisymmetric B− Se stretching frequency of BSe 2 is attributed to a pseudo-Jahn−Teller effect due to the mixing of the X 2 Π g ground state with the A 2 Π u excited state. In addition, H 2 BSe, HBSe, and HSeBSe molecules were produced in the reaction.

Activation of H2S by Atomic Cr, Mn, and Fe: Matrix Infrared Spectra and Quantum Chemical Calculations

“…The experimental setup for laser ablation and matrix isolation infrared spectroscopy has been described in detail previously. , Briefly, a fundamental Nd:YAG laser (1064 nm, 10 Hz repetition rate with 10 ns pulse width) was focused on a rotating metal target. The laser-ablated Cr, Mn, or Fe metal atoms were co-deposited with hydrogen sulfide diluted in an argon matrix (typically 0.3%) on a 5 K CsI window for 1 h. After sample co-deposition, the Fourier transform infrared spectra were recorded between 400 and 4000 cm –1 at 0.5 cm –1 resolution using a Bruker 80 V spectrometer with a liquid nitrogen-cooled broadband MCT detector.…”