Accession Number : ADA308323

Title :   Experimental Study of Unusual IR and Far IR Vibrational Energy Transfer Processes in Solids.

Descriptive Note : Final rept. 1 Aug 92-31 Jan 96,

Corporate Author : CORNELL UNIV ITHACA NY LAB OF ATOMIC AND SOLID STATE PHYSICS

Personal Author(s) : Sievers, A. J.

PDF Url : ADA308323

Report Date : 31 JAN 1996

Pagination or Media Count : 60

Abstract : Seven different experimental studies are described. (a) Hole burning in chalcogenide glasses: The dephasing time is a function of the average coordination number of the glass and is independent of the chemical composition. (b) Vibrational relaxation of diatomic molecules in alkali halide crystals: The matrix isolated CN- molecule obeys an energy gap law while the hydride molecule does not. (c) Vibrational relaxation of diatomic molecules in glass: Our IR pump - probe examination of SH in As2S3 glass has show that this impurity molecule is actually weakly hydrogen bonded in the glassy structure. (d) Pocket vibrational modes in crystals: A systematic study of a point defect in a crystal lattice has demonstrated that there are localized modes with the maximum mode amplitude at sites far removed from the defect itself. (e) Intrinsic localized vibrational modes in perfect crystals: The inclusion of both cubic and quartic terms in the potential has produced not only localized vibrational modes but also a localized dc expansion at the mode site. (f) Extinction sum rules for particles of arbitrary size: We have uncovered a general extinction sum rule which is independent of the size of the particle in relation to the wavelength and independent of the composite nature of the particle. (g) Measurement of a charged particle bunch from the coherent transition radiation mm-wave spectrum: The coherent far infrared radiation induced from relativistic electron bunches submillimeter length provides a new way to characterize the electron bunch shape.

Descriptors :   *INFRARED PHOTOCONDUCTORS, EXTINCTION, EXPERIMENTAL DATA, HYDRIDES, MOLECULAR VIBRATION, CRYSTAL LATTICES, ENERGY GAPS, ENERGY TRANSFER, CHARGED PARTICLES, GLASS, POINT DEFECTS, IMPURITIES, FAR INFRARED RADIATION, HALIDES, DIATOMIC MOLECULES, RELAXATION, SUBMILLIMETER WAVES, OPTICAL PUMPING, CHALCOGENS, ALKALI METAL COMPOUNDS.

Subject Categories : Infrared Detection and Detectors
      Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE