James L. Kinsey

Calculation of Interaction Matrix Elements for Asymmetric Rotors with Resultant Electronic Spin and Nuclear Spin

The application of Racah or vector recoupling coefficients to the calculation of interaction matrix elements for asymmetric rotors with resultant electronic and nuclear spin is outlined. This approach is compared with Van Vlecks method of reversed angular momenta.

Recurrences in the autocorrelation function governing the ultraviolet absorption spectra of O3

The approximate dipole–dipole autocorrelation function corresponding to UV photoabsorption in the Huggins and Hartley bands of ozone is obtained by Fourier transformation of the T=195 K data measured by Freeman, Yoshino, Esmond, and Parkinson [Planet. Space Sci. 32, 239 (1984)]. Weak structure seen at vibrational resolution in the broad absorption bands, previously unassigned, is shown to correspond predominantly to 4–5 small recurrent features in the autocorrelation function during the first 130 fs. These time‐dependent features are each assigned to particular types of unstable periodic or nearly periodic orbits in the classical dynamics.

High‐accuracy measurement of vibrational Raman bands of ozone at 266 and 270 nm excitations

Resonance Raman spectra of ozone at two excitation wavelengths (266 and 270 nm) have been measured up to 11 000 cm−1. Band origins have been measured to high accuracy and determined to within a few cm−1. Several bands beyond the dissociation limit have been observed. All prominent bands observed in this work fit to a two‐oscillator Darling–Dennison model. An analytical two‐dimensional potential energy surface has been constructed based on the new experimental data.

Quadrature integration for orthogonal wavelet systems

Wavelet systems can be used as bases in quantum mechanical applications where localization and scale are both important. General quadrature formulas are developed for accurate evaluation of integrals involving compact support wavelet families, and their use is demonstrated in examples of spectral analysis and integrals over anharmonic potentials. In contrast to usual expectations for these uniformly spaced basis functions, it is shown that nonuniform spacings of sample points are readily allowed. Adaptive wavelet quadrature schemes are also presented for the purpose of meeting specific accuracy criteria without excessive oversampling.

High precision dipole moments in à 1A2 formaldehyde determined via Stark quantum beat spectroscopy

The high resolution technique of Stark quantum beat spectroscopy is used to examine the electric dipole moment function for the first excited singlet state (A 1A2) of formaldehyde‐h2 and formaldehyde‐d2. The high precision of these measurements (i.e., better than 5 parts in 104) enables detailed determination of a‐axis dipole moment components (μa ) for individual J=2 rovibronic levels in the ν4 out‐of‐plane bending mode. In the case of 21,1 rotational levels, we find μa (40)=1.4784(7) D and μa (41)=1.4678(4) D for H2CO. For D2CO the measured 21,1 dipole moments are μa (40)=1.4698(6) D, μa (41)=1.4693(3) D, and μa (43) =1.4786(7) D. The state‐specific variations in μa revealed by this study reflect the structural influences exerted by the pervasive S1∼S0 nonadiabatic interactions and the pyramidally distorted equilibrium configuration which characterize the A state of formaldehyde. The origin and experimental manifestation of the out‐of‐plane dipole moment component (μc ) in nonrigid A 1A2 formaldehyde...

Microwave Spectrum of Chlorine Dioxide. V. The Stark and Zeeman Effects

The Stark and Zeeman effects of ClO2 have been observed in the rotational spectrum of ClO2. The dipole moment resulting from the Stark‐effect measurements is 1.784±0.01 D. The Zeeman effect was observed to fit the calculated spectrum for the interaction of a free electron with the magnetic field. The anisotropic components of the g factor are too small (about 1%) to be measured reliably with low magnetic fields.

Spectroscopy and dynamics of resonance Raman scattering by iodobenzene excited in the B continuum

Resonance Raman scattering in iodobenzene is studied for excitation in the region 219–233 nm (B 1A1←X 1A1). There is a rich Raman spectrum containing strong fundamentals of ring‐based modes and the CI stretch. On resonance, overtones and combination bands of most modes are strongly enhanced. The modulation of the CI stretch activity as a function of wavelength is interpreted in terms of the initial dynamical evolution of the molecule in the excited state. A normal mode analysis is also made of the ground‐state planar modes of iodobenzene in order to correlate the observations with the resonance Raman spectra in benzene.

Temperature dependence and dynamical instability in the Hartley absorption system of ozone

Analysis of weak oscillations in the Hartley absorption system of ozone via the equivalent recurrences in the autocorrelation function is found to reveal a clear temperature effect. Previous classical trajectory studies of unstable nearly periodic orbits associated with these oscillations/recurrences are extended to examine the possibility that strong sensitivity to initial rotational conditions is responsible. Using minimum return distance in phase space as an expedient measure for the stability of the orbits, evidence is found for particular destabilization due to in-plane rotations of the ozone molecule. A model for the recurrence temperature dependence is constructed based on this mechanism, and the implications for comparison of theoretical and experimental recurrence intensities are discussed.

Wavelets in curvilinear coordinate quantum calculations: H2+ electronic states

Multiscale wavelets are used to solve the quantum eigenvalue equations for the hydrogen molecular ion H2+ in the Born–Oppenheimer approximation. Normally restricted to Cartesian systems, “wavelets on the interval” (a normal wavelet family augmented by special edge functions) have recently been applied to such boundary value problems as the hydrogen atom in spherical polar coordinates [J. Mackey, J. L. Kinsey, and B. R. Johnson, J. Comp. Phys. 168, 356 (2001)]. These methods are extended here to ground and excited electronic states of the simplest molecule, for which the electronic Hamiltonian is separable in confocal elliptic coordinates. The set of curvilinear coordinate quantum systems for which wavelet bases have been applied is thus enlarged.

The determination of time cross correlation functions by inversion of Raman excitation profiles

Abstract The short-time dynamics of a nonstationary state is here determined by a direct inversion of an experimentally measurable Raman excitation profile. The procedure is based on the analytic properties of the Raman scattering amplitude and is best implemented within the maximum entropy formalism. A computational example for resonance Raman excitation profiles in the B state of iodobenzene is presented.