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Related papers: Molecular hydrogen in silicon: A path-integral sim…

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We investigate to what extent the specific heat of amorphous silica can be calculated within the harmonic approximation. For this we use molecular dynamics computer simulations to calculate, for a simple silica model (the BKS potential),…

Statistical Mechanics · Physics 2007-05-23 Jurgen Horbach , Walter Kob , Kurt Binder

We used one-dimensional coupled sine-Gordon equations combined with heat diffusion equations to numerically investigate the thermal and electromagnetic properties of a $300\,\mu\mathrm{m}$ long intrinsic Josephson junction stack consisting…

We conducted experiments on the role of molecular hydrogen physisorbed between two metallic surfaces. Such hydrogen leads to strong signatures in inelastic electron tunneling spectroscopy exceeding the amplitude of typical inelastic…

Mesoscale and Nanoscale Physics · Physics 2015-03-27 Matthias Stocker , Simon Röger , Berndt Koslowski

The reported diffusion constants for hydrogen in silicon vary over six orders of magnitude. This spread in measured values is caused by the different concentrations of defects in the silicon that has been studied. Hydrogen diffusion is…

Numerical studies of amorphous silicon in harmonic approximation show that the highest 3.5% of vibrational normal modes are localized. As vibrational frequency increases through the boundary separating localized from delocalized modes, near…

Disordered Systems and Neural Networks · Physics 2007-05-23 William Garber , Folkert M. Tangerman , Philip B. Allen , Joseph L. Feldman

Tight binding molecular dynamics simulations, with a non orthogonal basis set, are performed to study the fragmentation of carbon fullerenes doped with up to six silicon atoms. Both substitutional and adsorbed cases are considered. The…

Materials Science · Physics 2009-11-07 Chu-Chun Fu , Javier Fava , Ruben Weht , M. Weissmann

Amorphous hydrogenated silicon (a-Si:H) is an important material for surface defect passivation of photovoltaic silicon (Si) wafers in order to reduce their recombination losses. The material is however unstable with regards to hydrogen (H)…

Most of the studies addressed to computations of hydrogen parameters in semiconductor systems, such as silicon, are performed at zero temperature T=0 K and do not account for contribution of vibrational zero point energy (ZPE). For light…

Materials Science · Physics 2014-06-04 S. Zh. Karazhanov , M. Ganchenkova , E. S. Marstein

Using an optical centrifuge to control molecular rotation in an extremely broad range of angular momenta, we study coherent rotational dynamics of nitrogen molecules in the presence of collisions. We cover the range of rotational quantum…

Chemical Physics · Physics 2015-06-19 Alexander A. Milner , Aleksey Korobenko , John W. Hepburn , Valery Milner

We present a tight-binding calculation that, for the first time, accurately describes the structural, vibrational and elastic properties of amorphous silicon. We compute the interatomic force constants and find an unphysical feature of the…

Materials Science · Physics 2009-11-10 J. L. Feldman , N. Bernstein , D. A. Papaconstantopoulos , M. J. Mehl

The diffusional dynamics and vibrational spectroscopy of molecular hydrogen (H$_2$) in myoglobin (Mb) is characterized. Hydrogen has been implicated in a number of physiologically relevant processes, including cellular aging or…

Chemical Physics · Physics 2024-09-16 Jiri Käser , Kai Töpfer , Markus Meuwly

We use empirical molecular dynamics technique to study the low-energy vibrations in a large 4096 atom model for pure amorphous silicon and a set of models with voids of different size based on it. Numerical vibrational eigenvalues and…

Disordered Systems and Neural Networks · Physics 2009-10-31 Serge M. Nakhmanson , D. A. Drabold

Diffusion of atomic and molecular hydrogen in the interstitial space between graphite sheets has been studied by molecular dynamics simulations. Interatomic interactions were modeled by a tight-binding potential fitted to density-functional…

Materials Science · Physics 2011-08-12 Carlos P. Herrero , Rafael Ramirez

Water is an ubiquitous liquid that has several exotic and anomalous properties. Despite its apparent simple chemical formula, its capability of forming a dynamic network of hydrogen bonds leads to a rich variety of physics. Here we study…

Soft Condensed Matter · Physics 2023-08-15 R. Vuilleumier , A. P. Seitsonen

The sample dependence of various properties of hydrogenated amorphous silicon ($a$-Si:H) have been studied with 216 silicon atoms and 24 hydrogen atoms using the density functional based tight binding molecular dynamics simulations. The…

Other Condensed Matter · Physics 2009-11-10 Ranber Singh , S. Prakash , Nitya Nath Shukla , R. Prasad

Equilibrium properties of hydrogen-helium mixtures under conditions similar to the interior of giant gas planets are studied by means of first principle density functional molecular dynamics simulations. We investigate the molecular and…

Other Condensed Matter · Physics 2009-07-09 Jan Vorberger , I. Tamblyn , B. Militzer , S. A. Bonev

The calculation of the hindered roton-phonon energy levels of a hydrogen molecule in a confining potential with different symmetries is systematized for the case when the rotational angular momentum $J$ is a good quantum number. One goal of…

Condensed Matter · Physics 2009-11-07 T. Yildirim , A. B. Harris

We present the results of a large scale molecular dynamics computer simulation in which we investigated the static and dynamic properties of a silica melt in the temperature range in which the viscosity of the system changes from O(10^-2)…

Statistical Mechanics · Physics 2009-10-31 Jurgen Horbach , Walter Kob

Using a quantum-mechanical close-coupling method, we calculate cross sections for fine structure excitation and relaxation of Si and S atoms in collisions with atomic hydrogen. Rate coefficients are calculated over a range of temperatures…

Atomic Physics · Physics 2024-12-10 Pei-Gen Yan , James F. Babb

Molecular dynamics simulations are performed to study spatially heterogeneous dynamics in a model of viscous silica above and below the critical temperature of the mode coupling theory, $T_{MCT}$. Specifically, we follow the evolution of…

Soft Condensed Matter · Physics 2009-11-10 M. Vogel , S. C. Glotzer