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

Spectra of C2H2 in jet-cooled conditions and isolated in solid p-H2 are recorded. Spectra of C2H2 isolated in p-H2 show no evidence of rotation of C2H2. The strong interaction between ν3 and ν2 + ν4 + ν5 in the gas phase is diminished in solid p-H2.