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Areas of investigation summarized include nitrogen ion-nitrogen molecule collisions; molecular collisions with surfaces; molecular identification from analysis of cracking patterns of selected gases; computer modelling of a quadrupole mass spectrometer; study of space charge in a quadrupole; transmission of the 127 deg cylindrical electrostatic analyzer; and mass spectrometer data deconvolution.
Molecular collisions, formulating description as set of differential equations and developing eigenvectors and eigenvalues of Hermitian matrix associated with coupling
Aerodynamic molecular beam interactions with solid surfaces
Adiabatic approximation for nonreactive molecular collisions obtained from variational principle
Subexcitation molecular collisions resonances demonstrated by numerical solution of integral equations for rotational excitation, exhibiting adiabatic approximation limitations
Theory and analysis of relative motion and internal excitation in molecular collisions
The importance of the rigorous treatment of photon angular momentum in molecular-collision processes occurring in the presence of intense radiation is investigated. An alternate approximate treatment, which essentially neglects the angular momentum coupling between the photon and the molecular degrees of freedom by averaging over the angular dependence of the interaction matrix elements, is presented and applied to a model calculation. The degeneracy-averaged results of this calculation compare remarkably well with the results of a rigorous calculation, from which we conclude (with reservation) that the explicit consideration of photoangular momentum coupling in molecular-collision problems is unnecessary.
Distorted wave Magnus /DWM/ approximation for nonreactive molecular collisions, noting applicability in inelastic transition probabilities computation
Rotational excitation in diatomic molecular collisions to obtain equations for generalized set of phase shifts
Compound state resonances in molecular collisions, stressing scattering cross sections behavior for deuterium-xenon
Radiative transitions in molecular collision processes taking place in the presence of picosecond pulses are studied within a semiclassical formalism. An expression for adiabatic potential surfaces in the electronic-field representation is obtained, which directly leads to the evaluation of transition probabilities. Calculations with a Landau-Zener-type model indicate that picosecond pulses can be much more effective in inducing transitions than a single long pulse of the same intensity and the same total energy, if the intensity is sufficiently high that the perturbation treatment is not valid.
Nuclear spin effect on expressions for molecular collisions scattering cross sections using diagrammatic techniques
An introductory account of the semiclassical theory of the S-matrix for molecular collision processes is presented, with special emphasis on electronically nonadiabatic transitions. This theory is based on the incorporation of classical mechanics with quantum superposition, and in practice makes use of the analytic continuation of classical mechanics into the complex space of time domain. The relevant concepts of molecular scattering theory and related dynamical models are described and the formalism is developed and illustrated with simple examples - collinear collision of the A+BC type. The theory is then extended to include the effects of laser-induced nonadiabatic transitions. Two bound continuum processes collisional ionization and collision-induced emission also amenable to the same general semiclassical treatment are discussed.
The effect of the laser linewidth on molecular collision processes taking place in a laser field is studied, using an approximation scheme that replaces the actual frequency distribution of the field by a finite number of frequencies and weights. The choice of the frequencies and weights is conveniently accomplished by the method of Gaussian quadrature. Close-coupling calculations are performed on model systems, and the results indicate that the neglect of the laser linewidth may be justified in most collision processes in a laser field.
Collision cross sections direct measurement for determining macroscopic reaction rates in inelastic molecular collision processes in gas dynamics
Rotationally inelastic molecular collisions in atom rigid rotor scattering, considering infinite order approximation of generalized phase shift treatment
Exact solutions for two state potential curve crossing in subexcitation molecular collisions in terms of various decoupling schemes
A theory is reported which describes spectroscopic transitions between quasibound states formed during molecular collisions in a laser field. A preliminary calculation suggests that the shapes of absorption lines are sensitive to the shapes of the potentials; hence a method for determining the latter. The calculation also shows that respectable cross-sections for scattering can be obtained at low laser powers.