Low Temperature Physics: 26, 653 (2000); https://doi.org/10.1063/1.1312391 (8 pages)
Физика Низких Температур: Том 26, Выпуск 9-10 (Сентябрь 2000), c. 889-898 ( к оглавлению , назад )
Observation of the high resolution infrared absorption spectrum of CO2 molecules isolated in solid parahydrogen
Simon Tam and Mario E. Fajardo
Propulsion Directorate, U.S. Air Force Research Laboratory AFRL/PRSP, Bldg. 8451, Edwards AFB, CA 93524√7680
Received February 17, 2000, revised May 4, 2000
We report the observation of high resolution (0.008 cm-1) infrared absorption spectra of CO2 molecules isolated in solid parahydrogen(pH2) matrices at T=2.4 to 4.8 K. Several extremely sharp (0.01 to 0.04 cm-1 full-width-at-half-maximum) absorption features appear in the 2343.5 to 2345 cm-1
region. We assign the three strongest peaks to the n3 mode of isolated CO2 molecules. The spectra are consistent with trapping of the CO2 molecules in three distinct double-substitutional sites in hcp and fcc regions of the pH2 solid. We offer several hypotheses as to the origins of the numerous weaker absorption features.