Study of potential curves by UHF type methods. CH4 molecule and its dissociation products

1986 ◽  
Vol 51 (4) ◽  
pp. 731-737
Author(s):  
Viliam Klimo ◽  
Jozef Tiňo
Keyword(s):  
Experimental Data ◽  
Quantum Chemistry ◽  
High Energy ◽  
Basis Set ◽  
Electronic Correlation ◽  
Exact Methods ◽  
Energy Parameters ◽  
Bond Functions ◽  
The Individual ◽  
Potential Curves

Geometry and energy parameters of the individual dissociation intermediate steps of CH4 molecule, parameters of the barrier to linearity and singlet-triplet separation of the CH2 molecule have been calculated by means of the UMP method in the minimum basis set augmented with the bond functions. The results agree well with experimental data except for the geometry of CH2(1A1) and relatively high energy values of CH(2II) and CH2(1A1) where the existence of two UHF solutions indicates a necessity of description of the electronic correlation by more exact methods of quantum chemistry.

Study of potential curves by UHF type methods. Inversion and dissociation of NH3 molecule

1984 ◽  
Vol 49 (8) ◽  
pp. 1731-1735 ◽  
Author(s):  
Viliam Klimo ◽  
Jozef Tiňo
Keyword(s):  
Experimental Data ◽  
Saddle Point ◽  
Basis Set ◽  
Inversion Barrier ◽  
Exact Methods ◽  
Energy Parameters ◽  
Dissociation Energies ◽  
Bond Functions ◽  
Potential Curves ◽  
Good Agreement

Geometry and energy parameters of individual dissociation intermediate steps of the NH3 molecule, geometry of the saddle point, and the inversion barrier of NH3 have been calculated by the UMP2 method in the minimum basis set augmented with the bond functions. A good agreement has been reached with experimental data and with results of more exact methods except for the dissociation energies of the NH3 and NH2 molecules. New values of heats of formation are suggested on the basis of these results: ΔHfo0 = 197 and 362 kJ/mol for the NH2 and NH molecules, respectively.

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

Algorithms for determining the phase of RHEED oscillations

2015 ◽  
Vol 48 (6) ◽  
pp. 1927-1934 ◽  
Author(s):  
Zbigniew Mitura ◽  
Sergei L. Dudarev
Keyword(s):  
Experimental Data ◽  
Direct Method ◽  
Incident Beam ◽  
Diffraction Theory ◽  
High Energy ◽  
Angle Of Incidence ◽  
High Energy Electron ◽  
Dynamical Diffraction ◽  
Glancing Angle ◽  
Low Symmetry

Oscillations of reflection high-energy electron diffraction (RHEED) intensities are computed using dynamical diffraction theory. The phase of the oscillations is determined using two different approaches. In the first, direct, approach, the phase is determined by identifying the time needed to reach the second oscillation minimum. In the second approach, the phase is found using harmonic analysis. The two approaches are tested by applying them to oscillations simulated using dynamical diffraction theory. The phase of RHEED oscillations observed experimentally is also analysed. Experimental data on the variation of the phase as a function of the glancing angle of incidence, derived using the direct method, are compared with the values computed using both the direct and harmonic methods. For incident-beam azimuths corresponding to low-symmetry directions, both approaches produce similar results.

SOME CHARACTERISTICS OF THE COMPOUND MULTIPLICITY IN HIGH-ENERGY NUCLEUS–NUCLEUS INTERACTIONS

2011 ◽  
Vol 20 (08) ◽  
pp. 1735-1754 ◽  
Author(s):  
M. MOHERY ◽  
M. ARAFA
Keyword(s):  
Experimental Data ◽  
Impact Parameter ◽  
Mass Number ◽  
Multiplicity Distribution ◽  
High Energy ◽  
Projectile Nucleus ◽  
Target Mass ◽  
Compound Multiplicity ◽  
Multiplicity Distributions ◽  
The Impact

The present paper deals with the interactions of 22 Ne and 28 Si nuclei at (4.1–4.5)A GeV /c with emulsion. Some characteristics of the compound multiplicity nc given by the sum of the number of shower particles ns and grey particles ng have been investigated. The present experimental data are compared with the corresponding ones calculated according to modified cascade evaporation model (MCEM). The results reveal that the compound multiplicity distributions for these two reactions are consistent with the corresponding ones of MCEM data. It can also be seen that the peak of these distributions shifts towards a higher value of nc with increasing projectile mass. It may further be seen that the compound multiplicity distributions becomes broader with increasing target size and its width increases with the size of the projectile nucleus. In addition, it has been found that the MCEM can describe the compound multiplicity characteristics of the different projectile, target and the correlation between different emitted particles. The values of average compound multiplicity increase with increasing mass of the projectile. Furthermore, it is observed that while the value of 〈nc〉 depends on the mass number of the projectile Ap and the target mass number At, the value of the ratio 〈nc〉/D(nc) seems to be independent of Ap and At. The impact parameter is found to affect the shape of the compound multiplicity distribution. Finally, the dependence of the average compound multiplicity on the numbers of grey and black particles, and the sum of them, is obvious. The values of the slope have been found to be independent of the projectile nucleus.

Pseudorapidity distribution of relativistic singly charged particles in heavy-ion collisions at high energy

1999 ◽  
Vol 77 (4) ◽  
pp. 313-318 ◽  
Author(s):  
F -H Liu ◽  
Y A Panebratsev
Keyword(s):  
Experimental Data ◽  
Heavy Ion Collisions ◽  
Charged Particles ◽  
Heavy Ion ◽  
High Energy ◽  
Pseudorapidity Distribution ◽  
Ion Collisions ◽  
Singly Charged

The pseudorapidity distribution of relativistic singly charged particles produced in high-energy heavy-ion collisions is described by the thermalized cylinder picture. The calculated results are in agreement with the experimental data of lead-induced interactions at 158A GeV/c. PACS Nos.:25.75.-q and 25.75.Dw

A correlation to predict the performance characteristics of centrifugal pumps handling slurries

1997 ◽  
Vol 211 (2) ◽  
pp. 147-157 ◽  
Author(s):  
K A Kazim ◽  
B Maiti ◽  
P Chand
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Suspended Solids ◽  
Reduction Factor ◽  
Performance Characteristics ◽  
Centrifugal Pumps ◽  
Pump Performance ◽  
New Correlation ◽  
Effect Of Particle Size ◽  
The Individual

Centrifugal pumps are being used increasingly for transportation of slurries through pipelines. To design a slurry handling system it is essential to have a knowledge of the effects of suspended solids on the pump performance. A new correlation to predict the head reduction factor for centrifugal pumps handling solids has been developed. This correlation takes into account the individual effect of particle size, particle size distribution, specific gravity and concentration of solids on the centrifugal pump performance characteristics. The range of validity of the correlation has been verified by experiment and by using experimental data available from the literature. The present correlation shows better agreement with the experimental data than existing correlations.

Comparison of the Conformational Stability for Several Vinylhalomethanes and Silanes with Experiment Using MP2 Perturbation Theory and DFT

2007 ◽  
Vol 72 (1) ◽  
pp. 15-50 ◽  
Author(s):  
Wolfgang Förner ◽  
Hassan M. Badawi
Keyword(s):  
Experimental Data ◽  
Vibrational Spectra ◽  
Recent Literature ◽  
Conformational Stability ◽  
Basis Set ◽  
Major Conclusion ◽  
Stable Conformer ◽  
Polarization Functions ◽  
Complete Series ◽  
Triple Zeta

In recent literature it was reported that the valence triple zeta basis set augmented by polarization functions is not too reliable for vinyl monohalo- and dihalomethanes and -silanes, the halogen being fluorine and chlorine. The major conclusion was that a valence triple zeta basis is too small to be augmented by polarization functions in a balanced way, at least on vinylmonofluoromethane. Thus we decided to apply the 6-311++G** basis set to the complete series of methanes, silanes and germanes (the latter ones are just added for completeness because no experimental data are available for them and, moreover, we published them already previously) and to compare the results to experimental data available in the literature to see whether the failures of this basis set show up in the complete series of molecules. In the literature we found five such molecules and the information which of the conformers is the most stable. Indeed we found that predictions on the relative stability of conformers in those systems with this basis set and MP2 as well as DFT are with a 60:40 chance, three being correct predictions and two being incorrect ones out of the five. However, since the energy differences are rather small in these systems and due to the fact that - as a consequence of twofold degeneracy of the gauche conformer on the potential curve of the torsional vibration - the abundances of the conformers in equilibrium do not change too much, we decided to calculate also vibrational spectra for three examples and to compare them also to experiment. It is reported that besides the failures in total energy (we have chosen two examples where predictions of the nature of the stable conformer are correct, and one where it is not), the vibrational spectra are rather well reproduced, especially when experimental energies are used to calculate abundances in equilibrium in the case where the prediction of the stable conformer failed.

A Generalized Model for the Analysis of Groundwater Radiolysis

1984 ◽  
Vol 44 ◽  
Author(s):  
Stephen L. Nicolosi
Keyword(s):  
Experimental Data ◽  
Basis Set ◽  
Generalized Model

AbstractA generalized groundwater radiolysis model which is under development at Battelle-Columbus is described. This model uses a 55 reaction basis set for the radiolysis of the solvent. The basis set of reactions was chosen from the literature after comparing several descriptions against experimental data. This basis set has been augmented with 17 additional reactions to allow the description of the radiolysis of groundwater containing iron. The development of this mechanism is described, and comparisons with experimental data are shown.

THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: II. SPHERICAL GEOMETRY

1963 ◽  
Vol 41 (4) ◽  
pp. 651-663
Author(s):  
N. R. Steenberg
Keyword(s):  
Cross Section ◽  
Spherical Geometry ◽  
Monte Carlo Study ◽  
Nuclear Data ◽  
High Energy ◽  
Rare Gas ◽  
Nuclear Radius ◽  
Rigid Spheres ◽  
High Energy Radiation ◽  
The Individual

The absorption of radiation in a spherical obstacle composed of rigid spheres has been studied. The result is the absorption cross section of such an obstacle as a function of the free cross section and the number A of the individual spheres and of packing density. It is found that the usual rare-gas formula represents the cross section adequately. The analysis is applied to nuclear data for the absorption of 25-Bev/c protons by nuclei. It is found that for a nuclear radius R = r0A1/3 + δ, where δ is the radius of the nucleon, r0 = 1.17 fermi, δ = 1.05 fermi, and an average nucleon transparency a2 = 0.30 is consistent with the data.

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