The (5000) local mode vibrational state of germane: A high-resolution spectroscopic study

The high-resolution spectrum of natural abundant germane in the region 9775-9950 cm(-1) has been recorded. The observed spectrum is assigned as the (5000) stretching overtone band in local mode notation, which exhibits a striking resemblance to the K structure of parallel band of a symmetric top molecule. The observed transitions are analyzed in both the normal mode and the local mode pictures. The local mode vibration behavior of this state is also discussed. The stretch potential surface is optimized by least squares fitting the band centers of all the germane isotopic species. An alternative approach is proposed to calculate the effective vibration-rotational parameters using the vibrational wavefunction obtained by the anharmonically coupled anharmonic oscillators model. (C) 1997 Academic Press.