Rotationhyphen;Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing Paths. I. The Spectrum of Fluoroform (CHF3) from 2.4mgr; to 0.7mgr;

摘要

The spectrum of fluoroform has been investigated under high resolution (21‐ft. grating) in the photographic infra‐red with an absorbing path of up to 60 meters, obtained by multiple reflection according to the method of J. U. White. In addition, with the same path length the spectrum from 1.2 to 2.4&mgr; was obtained under low resolution with a photoelectric infra‐red spectrometer. A large number of overtone and combination bands, 47 in all, were found. Two parallel bands in the photographic region were well resolved and analyzed, yielding, for the moment of inertia about an axis perpendicular to the symmetry axis,IB[0]=81.08×10−40 g cm2From this value, assuming tetrahedral angles and a C&sngbnd;H distance as in methane, the C&sngbnd;F distance in fluoroform is found to be 1.329A, a value that is appreciably lower than that found in methyl fluoride, 1.380A. A provisional vibrational assignment of all the bands is given.