Coherent population transfer in molecules coupled with a dissipative environment by intense ultrashort chirped pulse. II. A simple model

We have developed a simple and physically clear picture of adiabatic rapid passage (ARP) in molecules in solution by careful examination of all the conditions needed for ARP. The relaxation effects were considered in the framework of the Landau-Zener model for random crossing of levels. The model enables us to include into consideration non-Markovian Gaussian-correlated noise. It explains all the numerical results obtained in the first paper of the series [B. D. Fainberg and V. A. Gorbunov, J. Chem. Phys. 117, 7222 (2002)], in particular, that for positive chirp pulse excitation relaxation favors more efficient population transfer with respect to the relaxation-free system with frozen nuclear motion. We also relate parameters of non-Markovian Gaussian-correlated noise with irreversible dephasing time of an optical transition by calculating the photon echo signal attenuation.     

Laminar boundary layer in flow of a nonequilibrium ionized gas

The motion of a hypersonic body is accompanied by an increase in the gas temperature in the boundary layer up to tens of thousands of degrees, which causes the gas to ionize. Under these conditions there are problems in calculating coefficients of viscosity, diffusion, and heat conduction. Investigations have shown that it is invalid to extrapolate the widely used approximations for transport coefficients in the high temperature region [1–3]. This paper considers the laminar boundary layer in the vicinity of the stagnation point of a blunt body in a stream of monatomic nonequilibrium ionized gas. The main thrust is a more accurate calculation of transport coefficients and an investigation of their effect on profiles of the gasdynamic parameters. A specific calculation is performed for argon by way of example.     

Connection between the Fokker-Planck-Kolmogorov and nonlinear Langevin equations

We recall the general proof of the statement that the behavior of every holonomic nonrelativistic system can be described in terms of the Langevin equation in Euclidean (imaginary) time such that for certain initial conditions, the different stochastic correlators (after averaging over the stochastic force) coincide with the quantum mechanical correlators. The Fokker-Planck-Kolmogorov (FPK) equation that follows from this Langevin equation is equivalent to the Schrödinger equation in Euclidean time if the Hamiltonian is Hermitian, the dynamics are described by potential forces, the vacuum state is normalizable, and there is an energy gap between the vacuum state and the first excited state. These conditions are necessary for proving the limit and ergodic theorems. For three solvable models with nonlinear Langevin equations, we prove that the corresponding Schrödinger equations satisfy all the above conditions and lead to local linear FPK equations with the derivative order not exceeding two. We also briefly discuss several subtle mathematical questions of stochastic calculus.     

Formation of lithium-like boron and nitrogen ions in the <Superscript>4</Superscript><Emphasis Type="Italic">P</Emphasis><Subscript>5/2</Subscript> state in gaseous media

We experimentally determined the fraction of α_v of lithium-like boron B²⁺ and nitrogen N⁴⁺ ions in the ⁴ P _5/2 state having a velocity of 3.6 au that are formed upon capture of two (α₂) electrons by hydrogen-like B⁴⁺ and N⁶⁺ ions and upon capture of one (α₁) electron by helium-like (1s2s)^1,3 S metastable B³⁺ and N⁵⁺ ions in gaseous media (H₂, He, N₂, Ar), as well as upon passage through a celluloid film. In light-element media (H₂, He), α₂ increases proportional to the target thickness T _g and reaches a maximum at T _g ≈ 10¹⁶ atom/cm² (for B ions, α₂ ≈ 0.2 in H₂ and α₂ ≈ 0.4 in He). For boron and nitrogen ions passing through thin layers of heavier gases (N₂, Ne), α₂ depends considerably more weakly on T _g , and, in Ar, becomes practically constant. It is assumed that, since hydrogen and helium do not contain electrons with parallel spins, autoionizing lithium-like ions are formed as a result of successive (one by one) capture of electrons, whereas, in the heavier gases, simultaneous capture of two electrons predominates. At T _g ～ 10¹⁵ atom/cm², the fraction α₁ of boron ions is the highest in He, ～0.15, and the lowest in Ar, ～0.07, being in qualitative agreement with calculations.     

A study on the isotope composition of carbon <Superscript>13</Superscript>C in poppy seeds and narcotic poppy straw present in the same package aimed at the revelation of the possible artificial superinducements of a narcotic substance

The rise in crime associated with the illicit trafficking in narcotics and psychotropic substances is one of the most severe problems in Russia today. In recent years, cases of using seeds of poppy plant “masked as food,” the bulk of which contains macroparticles of poppy straw visible to an unaided eye and which can be used as raw materials for the preparation of narcotic substances have become more frequent. In his work, using a Delta V Advantage isotopic mass spectrometer, we proposed criteria based on which tone can reveal artificial superinducements of poppy straw into “food” poppy seeds or their absence.     

Equivalence of the Duffin-Kemmer-Petiau and Klein-Gordon-Fock equations

A strict proof of the equivalence of the Duffin-Kemmer-Petiau and Klein-Gordon-Fock theories is presented for physical S-matrix elements in the case of charged scalar particles minimally interacting with an external or quantized electromagnetic field. The Hamiltonian canonical approach to the Duffin-Kemmer-Petiau theory is first developed in both the component and the matrix form. The theory is then quantized through the construction of the generating functional for the Green's functions, and the physical matrix elements of the S-matrix are proved to be relativistic invariants. The equivalence of the two theories is then proved for the matrix elements of the scattered scalar particles using the reduction formulas of Lehmann, Symanzik, and Zimmermann and for the many-photon Green's functions. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 124, No. 3, pp. 445–462, September, 2000.