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Articles you may be interested inThe isotropic spectrum of the CO2 Raman 2ν3 overtone: A line-mixing band shape analysis at pressures up to several tens of atmospheres J. Chem. Phys. 134, 224301 (2011); 10.1063/1.3596750 Extended assignments of the 3ν1+ν3 band of methane J. Chem. Phys. 102, 5126 (1995); 10.1063/1.469238 Selfbroadening and selfshifting of ammonia lines in the 2ν2 band J. Chem. Phys. 78, 665 (1983); 10.1063/1.444809 The relative intensity of the ν (CO) and ν (MC) Raman bands of M(CO)6 species (M=Cr, Mo, W)

An absorption band in gaseous ammonia a t 3 p is observed a t high resolution and attributed t o the doubly degenerate fundamental va. The constants v0=3442.9, Ao = A1 = 6.13, A1r = 0.29, and B I = 9.75cm.-'describe the band. Many of the observed lines are doublets. This doubling is a result of t h e inversion of the ammonia molecule and the value 1.1 cm.? is calculated for t h e inversion doubling of the 0010 state.

High resolution study of methane's 3ν1+ν3 vibrational overtone bandA multiple reflection Raman tube and a high dispersion quartz spectrograph were used to investigate the fine structure of the 1'3 band of gaseous methane. Sixty-eight maxima were measured, and evidence for all but one of the 15 theoretically predicted sub-branches was found. An evaluation of the rotational constants by combination relations for Raman and infrared frequencies gives three different B values for the upper vibrational state and surprisingly, three for the ground state. A more acceptable analysis, based on a single set of rotational constants for the ground state, B o=5.253 cm-1 and Do= 1.9x 10-4 cm-1 , leads to B1 values for the various branches in the range 5.202 to 5.235 cm-1 • The analysis gives 1'0= 3018.7 cm-1 and 11 =0.056. The constants obtained for the ground state are also used in an analysis of the 21'3 infrared band. 498This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 128.59.226.54 On: Mon, 08 Dec 2014 18:41:21