Goldanskii effect

Since Dr. Goldanskii says he is not familiar with Douzou s work, perhaps I can make some response to the question of Dr. Thomas. Douzou s observations definitely do not illustrate a Goldanskii effect. In my understanding, the essential point from Douzou experiments, focusing on enzyme kinetics at temperatures from above 0°C to substantially below, is that the kinetic parameters change in a continuous way. 

Judging from our present knowledge, such a description is far from the whole story. The article of Benderskii and Goldanskii [1992] addressed mostly the vast amount of experimental data accumulated thus far. On the other hand, the major applications of QTST involved gas-phase chemical reactions, where quantum effects were not dominant. All this implies that there is a gap between the possibilities offered by modern quantum theory and the problems of low-temperature chemistry, which apparently are the natural arena for testing this theory. This prompted us to propose a new look at this field, and to consistently describe the theoretical approaches which are adequate even at T = 0. 

In anisotropic crystals, the amplitudes of the atomic vibrations are essentially a function of the vibrational direction. As has been shown theoretically by Karyagin [72] and proved experimentally by Goldanskii et al. [48], this is accompanied by an anisotropic Lamb-Mossbauer factor/which in turn causes an asymmetry in quadra-pole split Mossbauer spectra, for example, in the case of 4 = 3/2, f = 1/2 nuclear transitions in polycrystalline absorbers. A detailed description of this phenomenon, called the Goldanskii-Karyagin effect, is given in [73]. The Lamb-Mossbauer factor is given by... 

NFS spectra recorded at 300 K for -cut and c-cut crystals are shown in Fig. 9.17 [48]. The/factors for the two orientations were derived from the speed-up of the nuclear decay (i.e., from the slope of the time-dependent intensity in Fig. 9.17a and from the slope of the envelope in Fig. 9.17b). The factors obtained f ( P = 0.122 (10) and f = 0.206(10) exhibit significant anisotropic vibrational behavior of iron in GNP. This anisotropy in f is the reason for the observed asymmetry in the line intensity of the quadrupole doublet (in a conventional Mossbauer spectrum in the energy domain) of a powder sample of GNP caused by the Goldanskii-Karyagin effect [49]. 

The relevance of the Mdssbauer effect to chemistry is that now one can reinvestigate compounds such as the tin tetrahalides which were previously thought to be understood. There are molecular orbital calculations, quoted by Goldanskii, based on the assumption that the tin tetrahalides are primarily covalent in character. 

I think we should now return to the key remarks made by Goldanskii. It appears that he is contrasting thermal effects of diffusion and reaction with quantum effects for which temperature is unimportant. 

Bourgin [51] and Roginsky and Rosenkewitsch [52] were the first to pay attention to the possibility of the tunnel mechanism of chemical reactions. They did so quite soon after the creation of quantum mechanics. At that time, the main features of this phenomenon were also understood on the qualitative level. Later on, a large number of theoretical and experimental works were dedicated to more detailed studies on tunnel effects in chemical reactions. This field has attracted the interest of scientists up to the present time. A comprehensive review of the history and the present state of investigations of nuclear tunneling in chemical reactions can be found in the recently published monographs by Bell [53] and Goldanskii et al. [54],... 

R.P. Bell, The Tunnel Effect in Chemistry, Chapman and Hall, London, New York, 1980. V.I. Goldanskii, L.N. Trakhtenberg and V.N. Flerov, Tunneling Phenomena in Chemical Physics, Nauka, Moscow, 1986 (in Russian). 

Goldanskii, V. I., Karyagin, S. V., Makarov, E. F., Khrapov, V. VDubna Conference on Mossbauer Effect, July, 1962, p. 189 (These conference proceedings have been published by Consultants Bureau, New York, 1963). 

Temperature and hydration level are linked in determining the dynamics of protein and solvent. The dry protein shows, for all temperatures, only the restricted motion found below the critical temperature for hydrated samples. A fully hydrated sample shows strong temperature dependence for the dynamic properties of both protein and hydration water, for temperatures above the critical temperature. Partially hydrated samples behave complexly. Goldanskii and Krupyanskii (1989) gave a particularly good discussion of the linkage between the effects of temperature and hydration. 

Goldanskii, V. I. The Mossbauer effect and its applications in chemistry. New York Consultants Bureau 1964. 

Benderskii, V., Goldanskii, V. and Makarov, D. (1991). Low-temperature chemical reactions. Effect of symmetrically coupled vibrations in collinear exchange reactions. Chem. Phys. 154, 407-424... 

Chemical Applications of Mossbauer Spectroscopy, ed. V. I. Goldanskii and R. H. Heher, Academic, New York, 1968 The Mossbauer Effect, Symp. Faraday Soc., 1, 1967. 

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