No abstract

A table of energy level patterns for rigid asymmetric rotors is given, by means of which this approximation to the rotational energies of all molecules up to J = 10 may be readily evaluated. The symmetry classification of each level is determined and expressed in terms of the K values of the limiting prolate- and oblate-symmetric rotors. A simple method is developed for calculating the transformation which diagonalizes the energy matrix and is applied to the derivation of perturbation formulas.

No abstract

A table of line strengths for rigid asymmetric rotors is given, by means of which to this approximation the relative intensities of all important rotational lines up to J < 13 for all bands of any molecule can be readily calculated, provided the asymmetry is roughly the same in the initial and final states. A classification of the irregularly spaced lines of the asymmetric rotor is made into ``sub-branches'' defined by the changes of the K values of the initial level in the limiting prolate and oblate symmetric rotors, and into ``wings'' which collect together lines of the sub-branches which have uniformly varying strength and Boltzmann factor, and fairly uniform spacing.

No abstract

Infra-red absorption spectra of polythene, rubber, polystyrene and polyvinyl chloride have been obtained at 4° absolute, in the rocksalt region, in a specially designed transmission cell containing liquid helium. No unusual changes occur on cooling which considerably alter the absorption. Some sharpening and improvement in resolution occurs, but the widths of most bands in polymers remain wide. In polythene one component of the doublet at 720 cm−1 becomes very sharp (possibly even less than the experimental value of the slit width, 1 cm−1). Its companion remains broad, about 4 cm−1. The two components are interpreted as CH2 wagging in trans- and cis-configurations of the hydro-carbon chain.

No abstract

The infrared spectra of six polynitro aromatic amines have been determined and found t o support chemical evidenceThe struc-Major improvements are reported in the synthesis of 3,5-that so-called pentanitrophenylmethylnitramine (I) is in reality a tetranitrophenylmethylnitramine (I11 or IV). ture of pentanitroaniline has been c o n b e d by infrared study. dinitroaniline and 3,5-dinitrcdimethylaniline.