Showing papers by "Willis B. Person published in 1972"

Spectroscopic Determination of the Barrier to Planarity in Cyclopentane

Abstract: A measurement of the Raman spectrum of cyclopentane in the gas phase under moderately high resolution reveals that the ground state radial transition at 272.5 cm−1 has two associated Q branches at 265.3 and 257.8 cm−1, corresponding to the first two excited transitions of the radial mode. With this information and the pseudorotational combination and difference bands with the CH2 deformation observed by During and Wertz, we have used both the perturbation treatment developed by Ikeda et al. and the direct matrix diagonalization program developed earlier to obtain the potential energy surface for cyclopentane in the ground state and in the first excited state of the CH2 deformation. In the ground state the barrier to planarity is found to be 1824 ± 50 cm−1 (5.21 kcal) and the equilibrium out‐of‐plane amplitude qe=0.47 ± 0.025 A.

Two-Dimensional Anharmonic Oscillator. Application to 2,5-Dihydrofuran

Abstract: A program has been developed to calculate the energy levels and corresponding wavefunctions for a two‐dimensional anharmonic potential surface of at least C2v symmetry This program has been employed to explain the high resolution splittings observed in the far infrared spectrum of 2,5‐dihydrofuran The magnitude of the cross term connecting the ring‐twisting and ring‐puckering modes of 2,5‐dihydrofuran is sufficiently large to be significant The potential surface determined also suggests that the ring‐twisting mode may be slightly anharmonic

New Methods for Studying Glass Corrosion Kinetics

Abstract: Infrared reflection spectroscopy and atomic emission spectroscopy have been applied to the study of glass corrosion using several new techniques that permit the kinetics of reactions near the surface to be measured on bulk samples as a function of applied stress, flow rate, temperature, time, pH, and relative humidity. Preliminary applications of these methods to the corrosion of a Li2O-2SiO2 glass are discussed. These new methods of studying the corrosion kinetics of glass under well defined conditions promise to aid in a better understanding of the nature of the reactions which take place at glass surfaces when subjected to various corrosive environments.

CNDO Calculation of Dipole Moment Derivatives and Infrared Intensities of C6H6 and C6F6

Abstract: The dipole moment derivatives of C6H6 and C6F6 have been calculated using the complete neglect of differential overlap (CNDO) approximate molecular orbital theory. The calculated set of derivatives with respect to the symmetry coordinates (∂ p/∂ Sj) for the e1u species of C6H6 agrees remarkably well with the unique experimental set of derivatives determined from infrared intensity measurements and the normal coordinate analysis for C6H6 and its deuterated analogues. The success of the benzene calculation suggests that we may have confidence in the CNDO results for C6F6, even though the agreement with the experimental results is much worse. An analysis of the ∂ p/∂ Sj values is given in terms of bond moment derivatives. The failure of the CNDO theory to predict a sufficiently large ``rehybridization moment'' to explain the observed intensity difference between in‐plane and out‐of‐plane bending vibrations is discussed.