THE ABSOLUTE INFRARED INTENSITIES OF PROPYNE-D0 AND PROPYNE-D3

The integrated infrared intensities of the fundamental modes of propyne-d0 and propyne-d3 have been measured by the Wilson-Wells-Penner-Weber method, using nitrogen as broadening gas at a pressure of 60 atm. From the measured intensities eight sets of ∂μ/∂S values were obtained using an iterative least-squares fitting procedure. The eight sets were left after fixing the signs of six ∂μ/∂S, parameters using CNDO and ab initio results and known values for related molecules. Four of the remaining sets were discarded after prediction of the propyne-d1 intensities. Using additional arguments from Coriolis interactions, predictive abilities and further comparison with related molecules one of the remaining four sets could be selected as the more preferable one. The final set ∂μ/∂Si values and the resulting calculated intensities are discussed and compared with the results of Kondo and Koga. The present sign combination is in full agreement with the ones selected by Kondo and Koga. Also the observed intensities, the ∂μ/∂Si values and the calculated intensities are in close accordance. © 1980 American Institute of Physics.