The ground state spectroscopic parameters and molecular geometry of SbH3

The rotation spectrum of stibine; SbH3, in the ground vibrational state was recorded in the region between 30 and 100 cm(-1) at an unapodized resolution of about 0.0015 cm(-1). Delta J = +1, Delta K = 0 transitions were measured and assigned up to J" = 15 and K = 12 for both Sb-121 arid Sb-123 isotopomers. The data of each molecule were analyzed together with the J=0, 1 rotational transitions reported in the literature, a few A(1)-A(2), K = 3 :splitting transitions and K = 1<--2, Delta K = 3 "perturbation allowed" transitions measured recently with Fourier transform microwave spectroscopy, and ground state combination differences from the analysis of the high resolution spectra of the stretching and bending fundamental bands. The theoretical models adopted for the analysis included Delta k = +/-3 or Delta k = +/-6 interaction terms and correspond to two different reductions of the rotational Hamiltonian. From the obtained parameters, the r(0) and the equilibrium structure were also determined for this molecule. (C) 1998 American Institute of Physics.