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Modelling the Role of Electronically Excited States in Laser‐Assisted Phenomena
Author(s) -
Wautelet M.,
Gehain E. D.,
Que P.
Publication year - 1988
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.2221490207
Subject(s) - excited state , excitation , covalent bond , atomic physics , laser , photon , chemistry , physics , quantum mechanics
From available relations between thermodynamical and microscopic parameters, the role of electronically excited sites on bond breaking and atomic migration is studied. It is demonstrated that, in covalent materials, electronic excitation leads to a decrease of the activation energy for bond breaking and migration, and of the entropy for migration, and to an increase of the entropy for bond breaking. It is also predicted that, under some circumstances, laser excitation might give rise to a decrease of reaction rate above a critical temperature, independent on the photon flux. The shift of the equilibrium position between competing processes is discussed, in the presence of selective excitation. The previous arguments are compared with available experimental data. Hints for future experiments are given.