HIGH-RESOLUTION FOURIER-TRANSFORM SPECTRUM OF THE NU(13) FUNDAMENTAL-BAND OF TRIACETYLENE IN THE FAR-INFRARED REGION

The lowest fundamental band nu(13) of triacetylene (HC6H) was measured in high resolution using a Fourier transform IR spectrometer in the range from 27 to 227 cm(-1). The resolution achieved was about 0.0018 cm(-1). The rotation-vibration band of nu(13) and the associated hot bands have been assigned using a computer-assisted Loomis-Wood diagram. Molecular constants for each vibrational state, i.e., the nu(13) = 1, 2, and 3 states as well as the ground state have been determined by a least-squares fit procedure using an effective Hamiltonian for linear molecules. The band origin of the nu(13) bending vibration was determined to be 105.038480(63) cm(-1). (C) 1994 Academic Press, Inc.