title: Infrared spectroscopy of the amide I mode of N-methylacetamide in solid hydrogen at 2-4 K.
abstract: We report high-resolution (0.05 cm(-1)) FTIR spectra of the fundamental and first overtone of the amide I mode of trans-N-methylacetamide (NMA) trapped in solid molecular hydrogen (SMH) at cryogenic temperatures with low (0.03%) and high (55%) ortho-hydrogen (oH(2)) concentrations. NMA-doped SMH samples with high oH(2) concentrations are nearly free from inhomogeneous broadening, permitting the measured amide I homogeneous line width of 1.268(8) cm(-1) to be used to place a lower limit on the vibrational lifetime of 4.19(3) ps. Direct observation of the amide I overtone allows the harmonic vibrational frequency ω(e) = 1726.6(5) cm(-1) and the anharmonicity constant ω(e)x(e) = 8.5(2) cm(-1) to be determined for NMA isolated in SMH samples with low oH(2) concentrations.
authors: Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071-3838, USA.
authors: Leif O
authors: LO
authors: Paulson
authors: David T
authors: DT
authors: Anderson
mesh_terms: D000081:Acetamides / Q000737:chemistry*; D003080:Cold Temperature; D006859:Hydrogen / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D000081:Acetamides; D006859:Hydrogen; C018595:N-methylacetamide