Infrared spectra of C2H2 under jet-cooled and para-H2 matrix conditions

In spectra of jet-cooled C2H2 recorded with an FTIR spectrometer, the v(5), v(4) + v(5), v(3) and v(2) + v(4) + v(5) bands all exhibit an intensity distribution corresponding to similar to 6 K for rotation, with no evidence of nuclear spin conversion. Spectra of C2H2 isolated in solid p-H-2 show no evidence of rotation of C2H2. The strong interaction between v(3) and v(2) + v(4) + v(5) in the gas phase is diminished in solid p-H-2. Lines associated with dimer, trimer and tetramer of C2H2 are identified. Spectral features characteristic of solid state acetylene are observed under jet-cooled conditions. (c) 2007 Elsevier B.V. All rights reserved.