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When molecules whose collision induced vibrational decay rates are small are probed by molecular absorption spectroscopic (MAS) techniques the absorption signal can, under certain conditions, be reduced and distorted. The reason has been…

Atomic Physics · Physics 2018-11-01 Thomas Hausmaninger , Weiguang Ma , Ove Axner

Prompted by recent experimental developments, a theory of surface scattering of fast atoms at grazing incidence is developed. The theory gives rise to a quantum mechanical limit for ordered surfaces that describes coherent diffraction peaks…

Atomic Physics · Physics 2022-09-23 J. R. Manson , Hocine Khemliche , Philippe Roncin

The aim of this article is a comprehensive description of normal modes of molecular vibrations. The starting point is chosen to be a general molecular system with separated center of mass and an arbitrary embedding of body-fixed axes. This…

Quantum Physics · Physics 2016-01-20 Emil Zak

The use of energy functionals based on density as the basic variable is advocated for ab initio molecular dynamics. It is demonstrated that the constraint of positivity of density can be incorporated easily by using square root density for…

Condensed Matter · Physics 2009-10-22 Vaishali Shah , Dinesh Nehete , D. G. Kanhere

Ab initio molecular dynamics calculations of deuterium desorbing from Si(100) have been performed in order to monitor the energy redistribution among the various D$_2$ and silicon degrees of freedom during the desorption process. The…

mtrl-th · Physics 2009-10-30 Axel Gross , Michel Bockstedte , Matthias Scheffler

Electronic absorption spectrum of beta-carotene (b-Car) is studied using quantum chemistry and quantum dynamics simulations. Vibrational normal modes were computed in optimized geometries of the electronic ground state S0 and the optically…

Chemical Physics · Physics 2023-06-14 Mantas Jakučionis , Ignas Gaižiūnas , Juozas Šulskus , Darius Abramavičius

The relation between ab initio molecular dynamics formalism and the electron-phonon interaction formalism [P.B. Allen and V. Heine, J. Phys. C 9, 2305 (1976)] is explored. The fundamental quantity obtained in the AIMD formalism - total…

Materials Science · Physics 2009-06-13 T. R. S. Prasanna

Accurate, non-contact temperature measurement with high spatial resolution is essential for understanding thermal behavior in integrated nanoscale devices and heterogeneous interfaces. However, existing techniques are often limited by the…

Materials Science · Physics 2026-03-13 Kun Yang , Chao Zhang , Chengwei Wu , Qian Du , Bingzhi Li , Zhen Fang , Liang Li , Jianbo Wu , Tianru Wu , Hui Wang , Tao Deng , Wenpei Gao

Ab initio molecular dynamics calculations of deuterium desorbing from Si(100) have been performed in order to monitor the energy redistribution among the hydrogen and silicon degrees of freedom during the desorption process. The…

mtrl-th · Physics 2008-02-03 Axel Gross , Michel Bockstedte , Matthias Scheffler

We have constructed models of quasi-periodic variability of X-ray emission from accreting compact objects. Assuming a general scenario of a propagation model of variability, with inverse Compton upscatering as the emission mechanism, we…

Astrophysics · Physics 2009-11-13 P. T. Zycki , M. Sobolewska

We present a general method for computing the gravitational radiation arising from the motion of bubble walls or thin fluid shells in cosmological phase transitions. We discuss the application of this method to different wall kinematics. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-03 Ariel Megevand , Federico Agustin Membiela

This paper explores the development and testing of a simple absorption correction model for processing x-ray powder diffraction data from Debye-Scherrer geometry laboratory x-ray experiments. This may be used as a pre-processing step before…

We present a theory of vibrational modulation of two-dimensional coherent Fourier transformed electronic spectra. Based on an expansion of the system's energy gap correlation function in terms of Huang-Rhys factors, we explain the…

We examine a new paradigm to account for the exponential decay seen in the light curves of some of the bright X-ray novae. These systems show an exponential decay in soft X-rays with an e-folding time constant of ~30 d. We investigate a…

Astrophysics · Physics 2009-10-31 J. K. Cannizzo

Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity…

This paper introduces an axiomatic approach in the theory of energy dissipation in Hilbert envelopes on waveforms emanating from various vibrating systems. A Hilbert envelope is a curve tangent to peak points on a motion waveform. The basic…

General Physics · Physics 2024-10-11 James F. Peters , Tharaka U. Liyanage

The bandgap of insulating materials is renormalized in various ways by the electron-phonon interaction owing to the dynamical and quantum fluctuations of nuclei. These fluctuation effects are considered in the perturbative…

Materials Science · Physics 2022-01-03 Kohei Ishii , Jun Haruyama , Osamu Sugino

We present an analytical theory of thermonuclear X-ray burst atmosphere structure. Newtonian gravity and diffusion approximation are assumed. Hydrodynamic and thermodynamic profiles are obtained as a numerical solution of the Cauchy problem…

Astrophysics · Physics 2009-11-07 Nickolai Shaposhnikov , Lev Titarchuk

We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband…

Optics · Physics 2016-07-20 R. J. Churchill , T. G. Philbin

The existing molecular relaxation models based on both parallel relaxation theory and series relaxation theory cannot extract the contributions of gas compositions to acoustic relaxation absorption in mixtures. In this paper, we propose an…

Chemical Physics · Physics 2017-12-21 Tingting Liu , Shu Wang , Ming Zhu