MÖSSBAUER EMISSION SPECTROSCOPY STUDIES OF TUNNELING CHEMICAL RELAXATION

V.I. Goldanskii; R.A. Stukan

doi:doi:10.1051/jphyscol:1980108

Numéro		J. Phys. Colloques Volume 41, Numéro C1, Janvier 1980 International Conference on Mössbauer Spectroscopy


Page(s)		C1-43 - C1-50
DOI		https://doi.org/10.1051/jphyscol:1980108

International Conference on Mössbauer Spectroscopy

J. Phys. Colloques 41 (1980) C1-43-C1-50
DOI: 10.1051/jphyscol:1980108

MÖSSBAUER EMISSION SPECTROSCOPY STUDIES OF TUNNELING CHEMICAL RELAXATION

V.I. Goldanskii et R.A. Stukan

Institute of Chemical Physics of the Academy of Sciences of the USSR, Vorobjevskoje Shausse, 2-b, Moscow, 117334, USSR

Abstract
The method of Mössbauer Emission Spectroscopy (MES) allows to study the kinetics of chemical conversions (electron and spin relaxation) of Mössbauer emitters if the time of such conversions [MATH] is comparable to the life-time of Mössbauer level [MATH]. Rate constants of fast interionic electron transfer from ⁵⁷Fe²⁺ (HS-high spin state) to [Fe(III)(CN)₆]^3- (LS-low spin state) in the transformation of Turnbull blue (TB) into the Prussian blue (PB) were measured at 400-I2 K by rapporteurs et al. (Moscow-Helsinki group) and it was found that the rate of this process reaches the low-temperature plateau value below ca.50 K. The observations of the rate of spin relaxation (HS→LS) for various dipyridyl and phenantroline complexes of iron performed by Mainz group at 293-4 K also have lead to the revealing of low-temperature plateau of the rate of such conversions. In such a way the MES has opened new possibilities of the studies of electron-nuclear tunneling which can be described on the base of the theory of the radiationless electron transitions.