Rotation-Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing Paths IV. The Spectrum of Methyl Fluoroform (CH3CF3) from 19μ to 0.7μ

Abstract

The absorption spectrum of methyl fluoroform has been investigated with path lengths up to 30 meters in the region 19 to 0.7μ. Three of the fundamentals have been assigned differently from Thompson and Temple. Since the molecule is nearly a spherical top, the ⊥ bands show the same typical PQR structure as do the ∥ bands except when the Coriolis interaction constant ζ is large. This seems to be the case for the degenerate C–F stretching vibration ν₉(e) and for most binary combinations involving it. The CH₃ rocking vibration ν₁₀(e) is split into two close components (separation 6 cm⁻¹) a splitting that is here ascribed to the presence of three potential minima separated by low potential maxima. A large number of infra‐red bands can be readily interpreted as binary combinations. The relative intensities of fundamentals and of overtone and combination bands are briefly discussed.