An ab initio calculation of the potential surface and rotation—vibration energies of the silyl radical

We have calculated 64 points on the ground electronic state potential energy surface of the silyl radical (SiH 3 ) using the MRD CI technique. This potential surface gives an inversion barrier of 1951 cm −1 and an equilibrium geometry of r e = 1.480 A and α e (HSiH) = 111.2°. Using the non-rigid invertor Hamiltonian with this potential we determine for SiH 3 that ν 1 = 2424 cm −1 , ν 2 = 778 cm −1 , ν 3 = 2106 cm −1 , and ν 4 = 976 cm −1 ; the inversion splitting is calculated to be 0.11 cm −1 . Rotational constants and centrifugal distortion constants have also been calculated.