Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

Technical Report · Thu Dec 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/5076664· OSTI ID:5076664

Wiesenfeld, J M

Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 ..mu..s, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5076664
• Report Number(s): LBL-7344
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
CHLORIDES
CHLORINE COMPOUNDS
COLLISIONS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DEUTERIUM COMPOUNDS
DIFFUSION
DIPOLES
ELEMENTS
ENERGY
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
FLUIDS
GASES
HALIDES
HALOGEN COMPOUNDS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETIC ENERGY
MATRICES
MULTIPOLES
NONMETALS
PHONONS
QUASI PARTICLES
RARE GASES
RELAXATION
RESONANCE
SOLIDS
VIBRATIONAL STATES