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J. C. López Vieyra

Bio: J. C. López Vieyra is an academic researcher from National Autonomous University of Mexico. The author has contributed to research in topics: Ground state & Renormalization group. The author has an hindex of 13, co-authored 57 publications receiving 410 citations.


Papers
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TL;DR: In this article, a detailed quantitative analysis of the system of two protons and one electron placed in a magnetic field ranging from 4.414 to 4.5 GHz is presented, and it is shown that in the domain of applicability of the nonrelativistic approximation the (ppe) system in the Born-Oppenheimer approximation has a well-pronounced minimum in the total energy at a finite interproton distance for $B\ensuremath{\lesssim}{10}^{11}\mathrm{G},$ thus manifesting the existence of the
Abstract: A detailed quantitative analysis of the system of two protons and one electron (ppe) placed in magnetic field ranging from ${10}^{9}\char21{}4.414\ifmmode\times\else\texttimes\fi{}{10}^{13}\mathrm{G}$ is presented. The present study is focused on the question of the existence of the molecular ion ${\mathrm{H}}_{2}^{+}$ in a magnetic field. A variational method with an optimization of the form of the vector potential (optimal gauge fixing) is used as a tool. It is shown that in the domain of applicability of the nonrelativistic approximation the (ppe) system in the Born-Oppenheimer approximation has a well-pronounced minimum in the total energy at a finite interproton distance for $B\ensuremath{\lesssim}{10}^{11}\mathrm{G},$ thus manifesting the existence of ${\mathrm{H}}_{2}^{+}.$ For $B\ensuremath{\gtrsim}{10}^{11}\mathrm{G}$ and large inclinations (of the molecular axis with respect to the magnetic line) the minimum disappears and hence the molecular ion ${\mathrm{H}}_{2}^{+}$ does not exist. It is shown that the most stable configuration of ${\mathrm{H}}_{2}^{+}$ always corresponds to protons situated along the magnetic line. With magnetic field growth the ${\mathrm{H}}_{2}^{+}$ ion becomes more and more tightly bound and compact, and the electronic distribution evolves from a two-peak to a one-peak pattern. The domain of inclinations where the ${\mathrm{H}}_{2}^{+}$ ion exists reduces with magnetic field increase and finally becomes $0\ifmmode^\circ\else\textdegree\fi{}\char21{}25\ifmmode^\circ\else\textdegree\fi{}$ at $B=4.414\ifmmode\times\else\texttimes\fi{}{10}^{13}\mathrm{G}.$ Phase-transition-type behavior of variational parameters for some interproton distances related to the beginning of the chemical reaction ${\mathrm{H}}_{2}^{+}\ensuremath{\leftrightarrow}\mathrm{H}+p$ is found.

29 citations

Journal ArticleDOI
TL;DR: In this article, a variational method is applied and the same trial function is used for different magnetic fields, where the magnetic field ranges from 10 − 9 − 9 to 4.3m.
Abstract: As a continuation of our previous work [Phys. Rev. A 68, 012504 (2003)] an accurate study of the lowest $1{\ensuremath{\sigma}}_{g}$ and the low-lying excited $1{\ensuremath{\sigma}}_{u}$, $2{\ensuremath{\sigma}}_{g}$, $1{\ensuremath{\pi}}_{u,g}$, $1{\ensuremath{\delta}}_{g,u}$ electronic states of the molecular ion $\mathrm{H}_{2}{}^{+}$ is made. Since the parallel configuration where the molecular axis coincides with the magnetic field direction is optimal, this is the only configuration which is considered. The variational method is applied and the same trial function is used for different magnetic fields. The magnetic field ranges from ${10}^{9}$ to $4.414\ifmmode\times\else\texttimes\fi{}{10}^{13}\phantom{\rule{0.3em}{0ex}}\mathrm{G}$, where nonrelativistic considerations are justified. Particular attention is paid to the $1{\ensuremath{\sigma}}_{u}$ state which was studied for an arbitrary inclination. For this state a one-parameter vector potential is used which is then variationally optimized.

24 citations

Journal ArticleDOI
TL;DR: Data-adaptive techniques from signal analysis are applied to decompose the spectrum in clearly differentiated trend and fluctuation modes, avoiding possible artifacts introduced by standard unfolding techniques.
Abstract: Spectra of ordered eigenvalues of finite random matrices are interpreted as a time series. Data-adaptive techniques from signal analysis are applied to decompose the spectrum in clearly differentiated trend and fluctuation modes, avoiding possible artifacts introduced by standard unfolding techniques. The fluctuation modes are scale invariant and follow different power laws for Poisson and Gaussian ensembles, which already during the unfolding allows one to distinguish the two cases.

24 citations

Journal ArticleDOI
TL;DR: In this paper, a nonrelativistic classification of charged molecular hydrogenic, helium, and mixed helium-hydrogenic chains with one or two electrons which can exist in a strong magnetic field $B\ensuremath{\lesssim}{10}^{16}$ G is given.
Abstract: A nonrelativistic classification of charged molecular hydrogenic, helium, and mixed helium-hydrogenic chains with one or two electrons which can exist in a strong magnetic field $B\ensuremath{\lesssim}{10}^{16}$ G is given. It is shown that for both $1e\ensuremath{-}2e$ cases at the strongest studied magnetic fields the longest hydrogenic chain contains at most five protons, indicating the existence of ${\mathrm{H}}_{5}{}^{4+}$ and ${\mathrm{H}}_{5}{}^{3+}$ ions, respectively. In the case of the helium chains, the longest chains can exist at the strongest studied magnetic fields with three and four $\ensuremath{\alpha}$ particles for $1e\ensuremath{-}2e$ cases with the possible existence of ${\mathrm{He}}_{3}{}^{5+}$ and ${\mathrm{He}}_{4}{}^{6+}$, respectively. For mixed helium-hydrogenic chains, the number of heavy centers can reach five for the highest magnetic fields studied. In general, for a fixed magnetic field, two-electron chains are more bound than one-electron chains.

22 citations

Journal ArticleDOI
TL;DR: An improved version of the liquid drop model is presented in this paper, where the addition of two terms, linear and quadratic in the total number of valence nucleons (particles or holes), improves the description of atomic masses, which can be fitted with an r.m.s.

22 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors derived the symmetry coefficients from Skyrme-Hartree-Fock (SHF) and IAS (Isobaric analog states) calculations on a nucleus-by-nucleus basis.

242 citations

Journal ArticleDOI
TL;DR: In this paper, the Hohenberg-Kohn energy functional was used to construct isoscalar and isovector densities for a half-infinite particle-stable nuclear-matter.

189 citations