Vibrational Spectrum and Gas-Phase Structure of Disulfur Dinitride (S_2N_2)

摘要

Gas-phase FTIR spectra of the υ_6 (B-type) and the υ_4 (C-type) fundamental bands of S_2N_2 (D_(2h)) were recorded with a resolution of ≤0.004 cm~(-1) and the vibrational spectrum of S_2N_2 (D_(2h)) in solid Ar has been revisited. All IR-active fundamentals and four combination bands were assigned in excellent agreement with calculated values from anharmonic VPT2 and VCI theory based on (explicitly correlated) coupled-cluster surfaces. Accurate experimental vibrational ground- and excited-state rotational constants of ~(32)S_2~(14)N_2 are obtained from a rovibrational analysis of the υ_6 and υ_4 fundamental bands, and precise zero-point average r_z (R_z(SN)=1.647694(95) ?, α_z(NSN)=91.1125(33)°) and semi-experimental equilibrium structures (R_e(SN)=1.64182(33) ?, α_e(NSN)=91.0716(93)°) of S_2N_2 have been established. These are compared to the solid-state structure of S_2N_2 and structural properties of related sulfur nitrogen compounds and to results of ab initio structure calculations.