The High-Resolution Raman Spectrum of the nu4 Band of Diborane

The high-resolution Raman spectra of the nu4 bands of 11B2H6 and 11B10BH6 have been recorded and analyzed. The recordings have been made using a high-resolution spectrometer based on the inverse Raman effect. Q branches have been observed, but P and R branches were too weak to be seen, and simulations of the observed band contour have been necessary to complete the analysis. A weak Coriolis resonance with the 2nu10 level is present in the 11B2H6 spectrum. The band centers obtained are 790.9829(12) and 804.76985(27) cm-1 for 11B2H6 and 10B11BH6, respectively (uncertainties are type A with a coverage factor k = 1, i.e., 1 standard deviation). Copyright 1999 Academic Press.