Simulation of the instability of axisymmetric vortices using the contour dynamics method

The two-dimensional problem of the stability of the circular motion of an ideal incompressible fluid with given radial vorticity distribution is studied.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 33–39, January–February, 1985.     

A Mössbauer study of some ferrocene derivatives

Mössbauer spectra (MS) are presented for twenty-four ferrocene derivatives. Substituents have relatively little effect on the hyperfine structure, butf and R vary greatly. The MS parameters are discussed in relation to the electronic structure of the iron atom and the dynamic features of the molecular crystals.     

Photo- and thermochromic spirans

The mechanisms of the valence isomerization of 2H-pyrans and chromene were calculated by means of the MINDO/3 method. A correlation between the magnitude of the barrier of activation of the electrocyclic reaction and the differences in the energies of the bonds of the tautomeric forms was noted. A simple scheme that makes it possible to estimate the magnitude of the activation barrier of the thermochromic transformations of spiropyrans on the basis of quantum-chemical calculations by the Pariser-Parr-Pople (PPP) method is proposed.See [1] for Communication 16.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 172–177, February, 1988.The authors thank V. A. Lokshin and N. A. Voloshin for providing us with data on the barriers of thermochromic transformations of spiropyrans.