Magnetotransport in two-dimensional electron gas at large filling factors

We derive the quantum Boltzmann equation for the two-dimensional electron gas in a magnetic field such that the filling factor $\nu \gg 1$. This equation describes all of the effects of the external fields on the impurity collision integral including Shubnikov-de Haas oscillations, smooth part of the magnetoresistance, and non-linear transport. Furthemore, we obtain quantitative results for the effect of the external microwave radiation on the linear and non-linear $dc$ transport in the system. Our findings are relevant for the description of the oscillating resistivity discovered by Zudov {\em et al.}, zero-resistance state discovered by Mani {\em et al.} and Zudov {\em et al.}, and for the microscopic justification of the model of Andreev {\em et al.}. We also present semiclassical picture for the qualitative consideration of the effects of the applied field on the collision integral.Comment: 28 pages, 19 figures; The discussion of the role of the effect of the microwave field on the distribution function is revised (see also cond-mat/0310668). Accepted in Phys. Rev.

Mass spectra of 9-sila-9,10-dihydro-3-azaanthracenes and their derivatives

Electron impact fragmentation of 18 compounds from the series of 9-sila-9,10-dihydro-3-azaanthracene has been studied. The Formation of [M RH]+ ions where R is a substituent at the silicon atom is the main fragmentation route for siladihydroazaanthracenes. C(10)-Oxo derivatives lead to [M R′]+ (maximum intensity ion) and [M R′ RH] ions. These regularities may be used for the identification and structural verification of the above compounds. A specific feature of the mass spectra of siladihydroazaanthracenes is the randomisation of the hydrogen atoms at the C(10) position with the hydrogen atoms of the pyridine and benzene rings of the siladihydroazaanthracene ring. © 1980

Mass spectrometric study of 2-keto(thio)tetrahydropyrimidine derivatives

The fragmentation pathways of 2-keto(thio)-6-methyl-5-carbethoxy(acetyl)-4-aryl-1,2,3,4-tetrahydropyrimidines were established using high resolution mass spectra and DADI spectra. An unusual rearrangement was observed, which involves cyclization of the aryl substituent in the 4 position with the oxygen of an ester group and elimination of a C2H5 radical. © 1989 Plenum Publishing Corporation