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The absorption spectrum of the SnH4molecule has been measured with Doppler limited resolution in the region 1903–1960 cm−1by means of a tunable diode laser spectrometer. IR transitions of the Qand Rbranches of allowed ν3(F2) and “forbidden” ν1(A1) bands were observed. These two states were found to be strongly mixed by the rotational-vibrational interaction, and as a consequence the ν1band appears in absorption. Wavenumbers of transitions to the ν1, ν3energy levels with the quantum number of angular momentum J= 1–15 have been obtained with an accuracy of about 0.001 cm−1. More than 230 transitions of the 120SnH4isotopic species were used for simultaneous analysis of the ν1, ν3resonance states. In this way 21 spectroscopic parameters of the upper states have been determined using a model Hamiltonian which explicitly takes into account the resonance interaction. The parameters obtained reproduced the experimental spectrum with r.m.s. discrepancy of 0.002 cm−1.

Academician B. M. Vul, a renowned physicist in the field of dielectrics, ferroelectrics and semiconductors, died on April 1985, at the age of 81. Born in the Ukraine in 1903, he graduated from the Electrotechnical Department of Kiev Polytechnical Institute in 1928 and in 1930-1932 did his post-graduate training under the great physicist A. F. Ioffe. Since 1934 and to his last days B. M. Vul headed a laboratory in Lebede Physical Institute of the USSR Academy of Sciences. It was there that he did his Ph.D. studies on electric breakdown of gases and solid dielectrics that were to win him wide recognition.