The hydrogen atom and the H+2 and HeH++ molecular ions inside prolate spheroidal boxes

Ley‐Koo, E.; Cruz, S. A.

doi:10.1063/1.441649

Cited by 99 publications

(123 citation statements)

References 11 publications

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“…The main characteristic in this phenomenon is the energy-level crossing induced by confinement where, for instance, a 3d state corresponds to a lower energy than a 4s state. Futhermore, even for the hydrogen atom, level inversion has been predicted as a consequence of confinement [23] and therefore a regular behavior of mean excitation energies should not be expected for confined quantum systems. Surprisingly, the basic density functional theory (DFT) employed here seems to reflect this behavior and a more thorough study is on call.…”

Section: Mean Excitation Energiesmentioning

confidence: 95%

Pressure effects on stopping power of solids for channeled ions

Pathak

Cruz

Soullard

2005

Radiation Effects and Defects in Solids

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Pressure effects on the energy loss of swift channeled ions through silicon are considered. This is accomplished by estimating the changes in orbital charge densities and the corresponding mean ionization potentials, induced by increasing pressure. The bulk density for the compressed material is obtained from available experimental information on the corresponding equation of state for pressures up to 11.3 GPa, beyond which a structural phase transformation occurs. The high pressure is simulated by first caging the individual Si atom in a small spherical volume V and estimated as P = −∂E/∂V , where E is the total electronic energy for a particular confinement volume. The energy is selfconsistently calculated through a recently developed shell-wise version of the Thomas-FermiDirac-Weizsäcker density functional, which compares favorably with ab initio calculations on the basis of a cluster model where the Si atom is surrounded by neon (helium) atoms (in a molecular scheme). The resulting individual electronic shell charge densities are then averaged along planar channels to find the effective charge densities needed in the channeling energy loss calculations for channeled ions. The position dependence of the energy loss in the channels for the free and high-pressure case is calculated for 5 MeV protons and alpha particles along the (1 1 0) planar channels.

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Section: Mean Excitation Energiesmentioning

confidence: 95%

Pressure effects on stopping power of solids for channeled ions

Pathak

Cruz

Soullard

2005

Radiation Effects and Defects in Solids

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“…Some people argue that this potential is realistic and its results can be compared with experimental data. In fact, to the best of our knowledge only four molecules, H + 2 , [21][22][23][24][25] HeH ++ , [21] H 2 , [26][27][28][29] and LiH [30] have been studied when they are submitted to spatial restrictions and all of them deal with one or two electrons (See a recent review by Ley-Koo [31] ). [16] Besides, this model has been useful to test exchange-correlation functionals designed within the Kohn-Sham density functional theory.…”

Section: Introductionmentioning

confidence: 99%

Electron Density Analysis for the H2+ System Confined by Hard Walls: The Chemical Bond Under Extreme Conditions

et al. 2019

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For the first time, the electron density of the H + 2 molecule is analyzed when this system is confined by spheroidal walls with an infinite potential. Typically, this system is studied to obtain information of the total energy and its components or to gain insight of some expected values when such a system is squeezed by this kind of confinement. However, this is the first report where the electron density and its derivatives, under the quantum theory of atoms in molecules (QTAIM), are analyzed to study the chemical bond involved with this molecule. This confinement induces an unexpected behavior of the chemical bond and gives an idea about atomic interactions under high pressures, where the QTAIM approach indicates that the chemical bond disappears. For strong confinements, there is a significant contribution of the electron kinetic energy and the nuclear-electron energy contribution can be neglected. Under this situation, the confined H + 2 system is another example where the notion of the topological atom given by the QTAIM is no longer suitable.

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“…Since then, different approaches using hard and soft box models to study confinement effects on H 2 + have been put forward, ranging from variational, 2-5 perturbative, 6,7 and accurate calculations. [8][9][10] Also, more sophisticated treatments of H 2 + subjected to different confining barrier potentials have been developed. 11,12 To the authors' knowledge, similar studies for the confined HeH 2 + system are scarce 4,8 and necessary.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10] Also, more sophisticated treatments of H 2 + subjected to different confining barrier potentials have been developed. 11,12 To the authors' knowledge, similar studies for the confined HeH 2 + system are scarce 4,8 and necessary. Note that all the foregoing treatments have as a common characteristic, the conservation of rotational symmetry around the internuclear axis, imposed by the confining potential.…”

Section: Introductionmentioning

confidence: 99%