Absolute fundamental and overtone OH and OD stretching intensities of alcohols.

Absolute intensities of the ΔvOH = 1 - 2 and ΔvOD = 1 - 3 transitions were determined for a range of alcohols (methanol, ethanol, 2-propanol, 1-propanol and tert-butanol) using conventional Fourier transform infrared (FTIR) spectroscopy. The intensities of the OH stretching transitions are stronger than the corresponding OD stretching transitions and become increasingly stronger with higher overtone transitions as expected from the reduced masses of the oscillators. Furthermore, accurate absolute intensities of the third and fourth OH stretching overtone transitions were determined using our newly constructed integrated cavity ring down (CRD) and FTIR spectrometer with experimental uncertainties generally less than 10%. The experiments were complemented by local mode calculations, with the potential energy surfaces and the dipole moment functions determined at the CCSD(T)/aug-cc-pVTZ level of theory. The calculated oscillator strengths of the ΔvOH = 4 - 5 transitions are within 25% of the experimental results.