Accession Number : ADA183166

Title :   Crossed Molecular Beam Studies.

Descriptive Note : Final rept. 1 Oct 81-30 Sep 84,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DEPT OF CHEMISTRY

Personal Author(s) : Herschbach,D. R.

Report Date : APR 1987

Pagination or Media Count : 33

Abstract : This report summarizes three of investigations: 1) studies of van der Waals collision dynamics, 2) laser spectroscopy study of rotational vibrational relaxations, and 3) angular correlations in chemical reactions. A cross molecular beam apparatus was used to study several van der Waals bond exchange reactions. These collisions involving extremely weak interactions were found to have product velocity distributions which resemble those from several ion molecular reactions which occur at very high collision energy. This led to the theoretical development of a scattering model which should be applicable to a wide range of reactive and inelastic collision processes at kinetic energies higher than the bond strengths. In another effort, laser induced fluorescence experiments were performed to measure the rotational and vibrational temperatures of molecular iodine seeded in beams of helium, argon, or nitrogen expanded from a supersonic nozzle. The results demonstrated the utility of seeded iodine fluorescence as a diagnostic for pulse shape and collisional relaxation in pulsed supersonic beams. Lastly, theoretical calculations dealing with rotational orientation in molecular collisions resulted in the formulation of a correlation analysis which offers a means to obtain information about collision dynamics that would otherwise be lost by averaging over the initial impact parameters and molecular orientations.

Descriptors :   *MOLECULAR BEAMS, ANGLES, CORRELATION, BONDED JOINTS, STRENGTH(MECHANICS), COLLISIONS, DYNAMICS, INTERACTIONS, LOW STRENGTH, ION ION INTERACTIONS, MOLECULAR PROPERTIES, ARGON, CHEMICAL REACTIONS, RELAXATION, CROSS BEAM DEVICES, ELASTIC PROPERTIES, KINETIC ENERGY, REACTION KINETICS, LASER INDUCED FLUORESCENCE, MOLECULES, ORIENTATION(DIRECTION), DISTRIBUTION, VELOCITY, PULSED LASERS, SUPERSONIC CHARACTERISTICS, ROTATION, MODELS, SCATTERING, SUPERSONIC NOZZLES, HIGH ENERGY, IODINE, SPECTROSCOPY, PULSES, SHAPE, VIBRATION, SEEDING, COMPUTATIONS, THEORY, RANGE(EXTREMES)

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE