Ab initio study of spectroscopic constants and anharmonic force field of AsH_2 radical

摘要

The equilibrium structure, spectroscopic constants and anharmonic force field of AsH_2 have been investigated at B3LYP, B3PW91 and MP2 methods employing the basis sets of cc-pVNZ and aug-cc-pVNZ (N ∈ {T, Q}), respectively. The computed geometries, rotational constants, part of vibrational frequencies, quartic and sextic centrifugal distortion constants are compared with the available experimental data or theoretical results. The other vibrational frequencies, equilibrium rotational constants, anharmonic constants, vibrationrotation interaction constants, cubic and quartic force constants of AsH_2 are also predicted for the first time. Furthermore, the calculated results show that the DFT method is superior to MP2 at the calculations of geometries, spectroscopic constants and force constants. The B3PW91/aug-cc-pVQZ results are more reliable. Our predictions can provide useful data for the experimental studies of the corresponding spectroscopic constants of AsH_2.