Continuum three-body states using the hyperspherical adiabatic basis set

2008 ◽  
Vol 44 (1-4) ◽  
pp. 371-373 ◽  
Author(s):  
P. Barletta ◽  
A. Kievsky
Keyword(s):  
Basis Set ◽  
Three Body ◽  
Hyperspherical Adiabatic

scholarly journals A Density Functional Tight Binding Model with an Extended Basis Set and Three-Body Repulsion for Hydrogen under Extreme Thermodynamic Conditions

2014 ◽  
Vol 118 (29) ◽  
pp. 5520-5528 ◽  
Author(s):  
Sriram Goverapet Srinivasan ◽  
Nir Goldman ◽  
Isaac Tamblyn ◽  
Sebastien Hamel ◽  
Michael Gaus
Keyword(s):  
Density Functional ◽  
Tight Binding ◽  
Basis Set ◽  
Tight Binding Model ◽  
Binding Model ◽  
Thermodynamic Conditions ◽  
Three Body ◽  
Extended Basis

AN AB INITIO STUDY OF INTERMOLECULAR INTERACTION OF HYDROGEN FLUORIDE TETRAMER

2006 ◽  
Vol 05 (02) ◽  
pp. 187-196 ◽  
Author(s):  
JINSHAN LI
Keyword(s):  
Interaction Energy ◽  
Intermolecular Interaction ◽  
Density Functional ◽  
Ring Structure ◽  
Membered Ring ◽  
Basis Set ◽  
Intermolecular Interaction Energy ◽  
B3lyp Method ◽  
Three Body ◽  
Intermolecular Distances

Possible HF tetramer geometries have been optimized employing the density functional B3LYP method and the aug-cc-pVQZ basis set. Deformation energy has been calculated at the B3LYP/aug-cc-pVQZ level. After the BSSE correction with the CP method, two-body intermolecular interaction energy, three-body nonadditive intermolecular interaction energy, and four-body nonadditive intermolecular interaction energy (Δ E c[4]) have been obtained at the levels of B3LYP/aug-cc–pVQZ, B3LYP/aug-cc-pVTZ//B3LYP/aug-cc-pVQZ, and MP2/aug-cc-pVTZ//B3LYP/aug-cc-pVQZ. Calculated results show that the three-body nonadditive intermolecular interaction energy is important for the optimized structures of HF tetramer. At the MP2/aug-cc-pVTZ//B3LYP/aug-cc-pVQZ level, the four-body nonadditive intermolecular interaction strength arrives at -4.5kJ/mol in the optimized eight-membered ring structure, but is extremely weak in other optimized structures. The comparison between MP2 and B3LYP calculated intermolecular interaction energies shows that the B3LYP method is applicable to the calculation of the intermolecular interaction energy of HF tetramer when the basis set reaches aug-cc-pVTZ. ΔEc[4] occupies 8–32% of the total intermolecular interaction energy when the intermolecular distances of the eight-membered ring structure are in the range of 1.06–1.37 Å.

scholarly journals MOMENTUM DISTRIBUTIONS FROM THREE-BODY DECAYING 9Be AND 9B RESONANCES

2011 ◽  
Vol 20 (04) ◽  
pp. 827-830
Author(s):  
R. ÁLVAREZ-RODRÍGUEZ ◽  
A. S. JENSEN ◽  
D. V. FEDOROV ◽  
E. GARRIDO
Keyword(s):  
Momentum Distributions ◽  
Three Body ◽  
Hyperspherical Adiabatic ◽  
Dalitz Plots

The complex-rotated hyperspherical adiabatic method is used to study the decay of low-lying 9 Be and 9 B resonances into α, α and n or p. We consider six low-lying resonances of 9 Be (1/2±, 3/2± and 5/2±) and one resonance of 9 B (5/2-) to compare with. The properties of the resonances at large distances are decisive for the momentum distributions of the three decaying fragments. Systematic detailed energy correlations of Dalitz plots are presented.

scholarly journals Determination of a Density Functional Tight Binding Model with an Extended Basis Set and Three-Body Repulsion for Carbon Under Extreme Pressures and Temperatures

2013 ◽  
Vol 117 (15) ◽  
pp. 7885-7894 ◽  
Author(s):  
Nir Goldman ◽  
Sriram Goverapet Srinivasan ◽  
Sebastien Hamel ◽  
Laurence E. Fried ◽  
Michael Gaus ◽  
...  
Keyword(s):  
Density Functional ◽  
Tight Binding ◽  
Basis Set ◽  
Tight Binding Model ◽  
Binding Model ◽  
Three Body ◽  
Extended Basis

scholarly journals New ab Initio Potential Energy Surfaces for the Renner-Teller Coupled 11A′ and 11A′′ States of CH2

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Haitao Ma ◽  
Chunfang Zhang ◽  
Zhijun Zhang ◽  
Xiaojun Liu ◽  
Wensheng Bian
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Electronic States ◽  
Nonlinear Least Squares ◽  
Basis Set ◽  
Least Squares Fit ◽  
Three Body ◽  
Energy Surfaces

New ab initio potential energy surfaces (PESs) for the two lowest-lying singlet 11A′ and 11A′′ electronic states of CH2, coupled by the Renner-Teller (RT) effect and meant for the spectroscopic study, are presented. The surfaces are constructed using a dual-level strategy. The internally contracted multireference configuration interaction calculations with the Davidson correction, using the aug-cc-pVQZ basis set, are employed to obtain 3042 points at the lower level. The core and core-valence correlation effects are taken into account in the ab initio calculations with a modified optimized aug-cc-pCVQZ basis set for the higher-level points. The analytical representations of these PESs, with the inclusion of the nonadiabatic RT terms, are obtained by the nonlinear least-squares fit of the calculated points to three-body expansion. Quantum dynamical calculations are performed on these PESs, and the computed vibronic energy levels for the two singlet electronic states are in excellent agreement with experiment.

scholarly journals A Study of L2 Approximations in Atomic Scattering

1990 ◽  
Vol 43 (5) ◽  
pp. 485 ◽  
Author(s):  
AT Stelbovics ◽  
T Winata
Keyword(s):  
Convergence Rates ◽  
Basis Set ◽  
Matrix Elements ◽  
Close Coupling ◽  
Set Size ◽  
Atomic Scattering ◽  
Impact Ionisation ◽  
Three Body ◽  
Continuum Function ◽  
The Continuum

The approximation of Coulomb continuum functions by an L 2 basis is studied using a Laguerre� function basis which can be extended to completeness. Also studied is the convergence rate of L2 approximations to Born matrix elements for electron impact ionisation as a function of basis�set size. This important class of matrix elements occurs in pseudo�state close-coupling calculations, accounting for scattering to the three�body continuum. Convergence rates in both cases are derived analytically and confirmed numerically. We find that the rate of pointwise convergence of L2 expansions to the continuum function is slow, and of conditional type; however, it is proven that the corresponding ionisation matrix elements converge geometrically, Our result agrees with the behaviour observed in pseudo�state calculations.

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