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Temperature‐dependent self‐trapped exciton relaxation in alkali halides: molecular dynamics study
Author(s) -
Song K. S.,
Williams R. T.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200672156
Subject(s) - picosecond , exciton , relaxation (psychology) , chemistry , cluster (spacecraft) , atomic physics , molecular dynamics , alkali metal , molecular physics , atmospheric temperature range , condensed matter physics , physics , thermodynamics , computational chemistry , quantum mechanics , psychology , social psychology , laser , organic chemistry , computer science , programming language
New molecular dynamics (MD) simulations of the relaxation of self‐trapped excitons (STE) in NaCl have been performed with a cluster size of 1055 atoms at temperatures in the range 15 K to 300 K. For the first time, significantly different relaxation end products are obtained at a given temperature depending on the choice of the intitial atomic positions and velocities. From 15 K to 65 K, either the STE or a Frenkel defect pair can be found at the end of a few picoseconds. Between 65 K and 150 K only Frenkel defects are found after the same interval. At 250 K and above, STEs and Frenkel defects are again both found as end products after a few picoseconds, presumably as a result of large amplitude atomic motions which hinder the coherent process to be discussed. Within a limited statistical basis, it has been possible to estimate a defect formation rate, which peaks around 100 K. The result is interpreted as an indication of stochastic resonance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)