Localization of vibrational states in crystalline structures containing distortions of the dynamic matrix

The problem of vibrations of a harmonic crystalline lattice containing distortions has been considered. Distortions are described by smooth functions which decay with distance from the nucleus of the distortion. Features of the spectrum of localized states have been determined and their number has been established.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 75–78, January, 1984.     

Does a static solution exist for a gravitating planar wall?

It is shown that, under very general assumptions, no static nonsingular solution of the general relativity equations exists for the gravitational field of an uniformly planar matter distribution.     

Features of the fluorine‐substituted acetaldehydes dynamics in the low‐lying electronic states: Quantum mechanical study of the CHF2CHO molecule lowest excited singlet state

The potential energy surface (PES) for the CHF₂CHO molecule in the excited S₁ state is calculated by the CASSCF method. The features of the 1‐ and 2‐D cross‐sections of PES are considered in comparison with those of the relative molecules. The vibrational frequencies are calculated in harmonic approximation and the vibrational energy levels for the inversion motion of the carbonyl fragment CCH_aO and for the torsion motion of the CHF₂‐top are calculated in anharmonic approximation by the 1‐ and 2‐D variational methods. The calculated data are compared with the experimental ones. The problems of the experimental data interpretation are considered. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002     

Classification of singular points in the polarization field of the cosmic microwave background and eigenvectors of the Stokes matrix

An analysis is made of the singularities of the polarization field of the cosmic microwave background, where the polarization is equal to zero. It is found that the classification of the singular points differs from the usual three types known in ordinary differential equations. The new statistical properties of the polarization field are discussed, and new methods to detect the presence of primordial tensor perturbations are indicated. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 6, 395–401 (25 March 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Radiation hydrodynamics of supernova shock breakouts

The first powerful burst of photon radiation in a supernova appears when the shock front is a few photon mean-free paths below the star photosphere. This is called “shock breakout” and it is the first observable event after the neutrino and gravitational wave bursts in core-collapsing supernovae. Any early information about collapse is vitally important for understanding the physics of explosion, constraining speed of neutrino propagation etc. Direct observations of shock breakouts have been carried out in a few supernovae. We discuss some puzzles related to those objects. Finally, we describe our current understanding of the most luminous (hyper-)supernovae. Their long living radiative shocks pause many interesting problems in numerical and laboratory astrophysics and may have important applications in cosmology.     

Resolving infall caustics in dark matter halos

It has been found that the phase space of dark matter particles assembling a galactic halo in cosmological N-body simulations well defines the fine grained structure. Recently accreted particles form distinctive velocity streams with high density contrast. For a fixed observer position, these streams lead to peaks in the velocity distribution. Overall structure is close to that emerging in the secondary infall model.