Line strengths of the ν3 - ν4 band of methane

Abstract Strengths of 413 lines of the ν 3 - ν 4 band of methane from 1568 to 1932 cm −1 have been measured with 2 to 4% accuracies using spectra recorded at 0.011 cm −1 (unapodized) resolution. Transition strengths up to J 3 = 14 have been fitted with a standard deviation of 4% using a four-term, first-order expansion of the dipole moment. A band strength of 0.050(2) cm −2 atm −1 at 296 K is reported for ν 3 - ν 4 of 12 CH 4 . Estimated band strengths of ν 1 - ν 4 , ν 3 - ν 2 , ν 3 + ν 4 , ν 1 + ν 4 , and ν 2 + ν 3 are also given.

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