Monte-Carlo Study of Energy Losses in Hot Stage of Electronic Excitation Relaxation in Scintillators

1994 ◽  
Vol 348 ◽  
Author(s):  
Roman A. Glukhov ◽  
Andrey N. Vasil'ev
Keyword(s):  
Monte Carlo ◽  
Electronic Excitation ◽  
Particle Distribution ◽  
Monte Carlo Study ◽  
Energy Relaxation ◽  
Luminescence Decay ◽  
Distribution Functions ◽  
Photon Absorption ◽  
Energy Losses ◽  
Main Attention

ABSTRACTThe results of computer simulation of the fast stages of energy relaxation in insulators after the VUV or XUV photon absorption are presented. The simulation involves two stages:the inelastic scattering of excitations with production of secondary excitations and thermalization through phonon emission. The main attention is focused on the spatial distribution functions of excitations, i.e. one-particle and two-particle distribution functions.The latter Function determines the energy transfer at final stages of energy relaxation and is important for different quenching processes and the acceleration of the luminescence decay. The Monte-Carlo simulation was carried out for BaF2 crystal for photon energies from 20 eV to 100 eV. The simulation shows that the two-particle distribution functions and thus the kinetics depend on the energy of excitation.

Grand ensemble Monte Carlo calculation of the thermodynamic properties of a solid/vapour interface

1976 ◽  
Vol 29 (10) ◽  
pp. 2103 ◽  
Author(s):  
JE Lane ◽  
TH Spurling
Keyword(s):  
Monte Carlo ◽  
Thermodynamic Properties ◽  
Particle Distribution ◽  
Canonical Ensemble ◽  
Monte Carlo Calculation ◽  
Distribution Functions ◽  
Surface Phase ◽  
Ensemble Monte Carlo ◽  
Surface Phase Transitions ◽  
Grand Canonical

The thermodynamic properties of the krypton/graphite interface have been evaluated by the grand canonical ensemble Monte Carlo method. Submonolayer adsorption isotherms have been calculated at temperatures of 77.31, 84.11 and 90.12 K, together with particle distribution functions, surface pressures and isosteric heats of adsorption. The results are compared with experiment and discussed in relation to the existence of surface phase transitions. The Monte Carlo adsorptions were used to check the error in assuming Henry's law adsorption at low pressure.

One-Diohliensilonall A + B = 0 Reactmion with One Immobile Species

1992 ◽  
Vol 290 ◽  
Author(s):  
Panos Argyrakisa ◽  
Raoul Kopelman
Keyword(s):  
Monte Carlo ◽  
Particle Distribution ◽  
Rate Coefficient ◽  
Reaction Order ◽  
Distribution Functions ◽  
Relative Mobility ◽  
Subtle Difference ◽  
Density Profiles ◽  
Dimensional Lattice ◽  
One Dimensional

AbstractThe elementary batch reaction A + B = 0 is re-examined via Monte-Carlo simulations on a one-dimensional lattice. The relative mobility of the A and B species is varied in this model, but the initial densities of the A and B are always the same. We calculate the rates, the density profiles, and the particle distribution functions. The rate power law is conserved, i.e., the well-known 1/4 behavior is established for all mobilities. The rate coefficient is the only mobility-dependent quantity. The interparticle distribution functions show that the aggregation depends on the relative mobility but the segregation does not. This subtle difference has no effect on the asymptotic reaction order, which is close to 5.

Cluster Formation in a Concentrated Lithium-Liquid Ammonia Solution. A Monte Carlo Study

1997 ◽  
Vol 52 (11) ◽  
pp. 828-834 ◽  
Author(s):  
S. Hannongbua ◽  
S. Kokpol ◽  
Z. Gurskii ◽  
K. Heinzinger
Keyword(s):  
Monte Carlo ◽  
Liquid Ammonia ◽  
Cluster Formation ◽  
Lithium Ion ◽  
Monte Carlo Study ◽  
Solvation Shell ◽  
Ammonia Solution ◽  
Distribution Functions ◽  
Octahedral Plane ◽  
Explicit Consideration

Abstract Results of a Monte Carlo study of a lithium-liquid ammonia solution at 240 K are reported. The basic cube contained 135 Li+ and 1025 NH3 . With an experimental density of 0.554 g/cm3 a side-length of 37.89 Å resulted. The pseudopotential theory is employed, which permits the exclusion of the electrons from an explicit consideration. The structure of the solution is described by various site-site radial distribution functions. The six ammonia molecules in the first solvation shell of the lithium ion are arranged octahedrally. Clusters are formed which consist almost exclusively of two solvated Li+ which have simultaneously either one ammonia molecule or an octahedral edge or an octahedral plane in common. About one third of the ammonia molecules belong to the bulk phase.

A Monte Carlo Study of Insoluble Block Orientations in Swollen Cores of Multimolecular Block Copolymer Micelles

1994 ◽  
Vol 59 (4) ◽  
pp. 803-819 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Distribution Functions ◽  
Excluded Volume Effect ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
End To End ◽  
Tethered Chains ◽  
Self Avoiding Walk

Conformations of tethered chains in restricted spherical volumes with an increasing radius were studied by Monte Carlo simulations. Simulations were performed on a tetrahedral lattice at relatively high densities of the occupied lattice sites. A simultaneous self-avoiding walk of all tethered chains creates the starting conformations of the multi-chain system which are futher equilibrated by a modified algorithm similar to that of Siepmann and Frenkel. In this paper, only a geometric excluded volume effect of segments is considered. Selectively chosen series of data for changing numbers of chains, N, their lengths, L, and radii of the sphere, R, give information on the system behavior under various conditions. In this part of our systematic study of tethered chains in constrained volumes, we present angular distribution functions of the end-to-end, end-to-gravity center distances, etc. for system studied in previous paper. The second class of studied conformational characteristics are the distributions of projections of the end-to-end vectors into the selected directions (i.e. the radial direction and the direction of the first-to-second polymer segment connection).

Tethered Chains in Concave Volumes. A Monte Carlo Study

1994 ◽  
Vol 59 (10) ◽  
pp. 2166-2189 ◽  
Author(s):  
Karel Procházka ◽  
Zuzana Limpouchová
Keyword(s):  
Monte Carlo ◽  
Spherical Cavity ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Distribution Functions ◽  
Spherical Cavities ◽  
Chain Conformations ◽  
Tethered Chains ◽  
Self Avoiding Walk ◽  
Tethered Chain

Monte Carlo study of tethered chain conformations in spherical cavities was performed in a relatively broad range of average segment densities (i.e. numbers of tethered chains with increasing length in the sphere). Simulations were performed on a tetrahedral lattice using (i) an equilibrated self-avoiding walk for systems containing a single tethered chain with increasing length, and (ii) a simultaneous self-avoiding walk of many tethered chains in the spherical cavity together with equilibration of the system which was performed by a modified algorithm similar to that of Siepmann and Frenkel. Only a geometric excluded volume effect of segments was considered (i.e. the prohibition principle of a double occupancy of one lattice site by two different segments). Various distribution functions (e.g. distribution of the end-to-end and the end-to-gravity center distances and their orientations with respect either to the radial direction, or to the direction of the first-to-second segment connection, etc.) were calculated and the effect of increasing average segment density in the sphere on conformational characteristics of individual chains was studied. It was found that conformational and orientational properties of relatively short tethered chains are only little affected by increasing segment density (i.e. by the number of chains in the spherical cavity), whereas arrangements of long tethered chains are significantly influenced by the density of the system.

Electron Momentum and Energy Relaxation Times in Wurtzite GaN, InN and AlN: A Monte Carlo Study

2017 ◽  
Vol 47 (2) ◽  
pp. 1560-1568 ◽  
Author(s):  
Shulong Wang ◽  
Yanliu Dou ◽  
Hongxia Liu ◽  
Zhiyu Lin ◽  
Hailin Zhang
Keyword(s):  
Monte Carlo ◽  
Relaxation Times ◽  
Monte Carlo Study ◽  
Energy Relaxation ◽  
Electron Momentum

Analyzing Observed Composite Differences Across Groups

Methodology ◽  
2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Holger Steinmetz
Keyword(s):  
Monte Carlo ◽  
Structural Equation Modeling ◽  
Measurement Invariance ◽  
Structural Equation ◽  
Monte Carlo Study ◽  
Equation Modeling ◽  
Factor Loadings ◽  
Latent Mean Differences ◽  
Partial Invariance ◽  
Mean Differences

Although the use of structural equation modeling has increased during the last decades, the typical procedure to investigate mean differences across groups is still to create an observed composite score from several indicators and to compare the composite’s mean across the groups. Whereas the structural equation modeling literature has emphasized that a comparison of latent means presupposes equal factor loadings and indicator intercepts for most of the indicators (i.e., partial invariance), it is still unknown if partial invariance is sufficient when relying on observed composites. This Monte-Carlo study investigated whether one or two unequal factor loadings and indicator intercepts in a composite can lead to wrong conclusions regarding latent mean differences. Results show that unequal indicator intercepts substantially affect the composite mean difference and the probability of a significant composite difference. In contrast, unequal factor loadings demonstrate only small effects. It is concluded that analyses of composite differences are only warranted in conditions of full measurement invariance, and the author recommends the analyses of latent mean differences with structural equation modeling instead.

Sign in / Sign up

Export Citation Format

Share Document