Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
The breaking and remaking of a bond: Caging of 12in solid Kr R. Zadoyan, Z. Li, C. C. Martens, and V. A. Apkarian
 

Summary: The breaking and remaking of a bond: Caging of 12in solid Kr
R. Zadoyan, Z. Li, C. C. Martens, and V. A. Apkarian
Department of Chemistry, University of California, Irvine, California 92717
(Received 29 June 1994; accepted 6 July 1994)
The caging of I2 in solid Kr is followed in real-time following its dissociative excitation on the
A ( 31'1t.) surface. The experiments involve pump-probe measurements with a time resolution of
2 150 fs. The experimental signals are reproduced using classical molecular dynamics simulations,
and the classical Franck approximation. The comparison between experiment and simulation allows
an unambiguous interpretation of features in the observed signal as being due to the initial impulsive
stretch of the I-I bond, collision of the atoms with the cage wall, recoil and recombination, and the
subsequent coherent oscillations of the nascent I, molecule. These detailed observations are possible
due to retention of coherence along the I-I coordinate throughout the caging process. The extent of
coherence is dictated mainly by the initial impact parameters of the molecule-cage collision, which
in turn is controlled by the thermal and zero-point amplitudes of lattice vibrations. The caging is
well-described as a sudden process, involving a binary collision between I and Kr atoms with nearly
complete energy loss of the I atom upon completion of the first collision. Vibrational relaxation of
the bound molecule proceeds on the time scale of 12 ps. The nontrivial relation between this
relaxation time and decay rates that may be extracted from experimental transients is discussed.
Although the interplay between the nested A and A 'potentials is not detectable, it is clear that in the
studied range of initial excess energies, 1000-1700 cm-`, the recombination remains effectively

  

Source: Apkarian, V. Ara - Department of Chemistry, University of California, Irvine

 

Collections: Chemistry