Study of microwave pressure lineshifts: Dynamic and isotopic dependences

The study of pressure lineshifts and line broadenings initiated earlier (J. Mol. Spectrosc.94, 264–282 (1982)) is extended to some other perturbing gases and to isotopic species. New dependences of the lineshifts on the molecular parameters are found. One of them is the dependence, as well as the proportionality of the lineshift to the line frequency found before is explained in terms of a “dynamic Stark effect” model. The dependence of the lineshifts on the isotopic composition of the absorbing molecule is also reported. One of the main results of the study is the demonstration of higher sensitivity of lineshifts to the characteristics of molecular interactions as compared to the corresponding line broadening.     

Quark-antiquark composite systems: The Bethe-Salpeter equation in the spectral-integration technique

The Bethe-Salpeter equations for the quark-antiquark composite systems, q\(\bar q\), are written in terms of spectral integrals. For the q\(\bar q\) mesons characterized by the mass M, spin J, and radial quantum number n, the equations are presented for the following (n, M²) trajectories: π _J , η _J , a _J , f _J , ρ _J , ω _J , h _J , and b _J .     

Concentrated solutions for internal wave equations

We consider the propagation of internal gravity waves in a stratified fluid layer with a current. Formal asymptotic solutions concentrated in the horizontal plane are constructed for the linearized system of equations in the Boussinesq approximation. The complex space-time ray method is used.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 148, pp. 120–132, 1985.