arXiv subjects

Jesus M. Ugalde

Publications and source records attributed to Jesus M. Ugalde.

4 recordsLinked to original sources

arXiv2021

A Chirality-Based Quantum Leap

Chiral degrees of freedom occur in matter and in electromagnetic fields and constitute an area of research that is experiencing renewed interest driven by recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterials. The CISS effect underpins the fact that charge transport through nanoscopic chiral structures favors a particular electronic spin orientation, resulting in large room-temperature spin polarizations. Observations of the CISS effect suggest opportunities for spin control and for the design and fabrication of room-temperature quantum devices from the bottom up, with atomic-scale precision. Any technology that relies on optimal charge transport, including quantum devices for logic, sensing, and storage, may benefit from chiral quantum properties. These properties can be theoretically and experimentally investigated from a quantum information perspective, which is presently lacking. There are uncharted implications for the quantum sciences once chiral couplings can be engineered to control the storage, transduction, and manipulation of quantum information. This forward-looking perspective provides a survey of the experimental and theoretical fundamentals of chiral-influenced quantum effects, and presents a vision for their future roles in enabling room-temperature quantum technologies.

cond-mat.mes-hall↗

arXiv2020

Chemical Reactivity Studies by the Natural-Orbital-Functional 2nd-Order-Moller-Plesset (NOF-MP2) method. Water Dehydrogenation by the Scandium Cation

The reliability of the recently proposed natural orbital functional supplemented with second-order Møller-Plesset calculations, (NOF-MP2), has been assessed for the mechanistic studies of elementary reactions of transition metal compounds by investigating the dehydrogenation of water by the scandium cation. Both high- and low-spin state potential energy surfaces have been searched thoroughly. Special attention has been paid to the assessment of the capability of the NOF-MP2 method to describe the strong, both static and dynamic, electron correlation effects on the reactivity of Sc+(3D,1D) with water. In agreement with experimental observations, our calculations correctly predict that the only exothermic products are the lowest-lying ScO+(1Σ) and H2(1Σ_g+) species. Nevertheless, an in-depth analysis of the reaction paths leading to several additional products was carried out, including the characterization of various minima and several key transition states. Our results have been compared with the highly accurate multiconfigurational supplemented with quasi degenerate perturbation theory, MCQDPT, wavefunction-type calculations, and with the available experimental data. It is observed that NOF-MP2 is able to give a satisfactorily quantitative agreement, with a performance on par with that of the MCQDPT method.

physics.chem-ph↗

arXiv2019

The Coulomb Hole of the Ne atom

We analyze the Coulomb hole of Ne from highly-accurate CISD wave functions obtained from optimized even-tempered basis sets. Using a two-fold extrapolation procedure we obtain highly accurate results that recover 97\% of the correlation energy. We confirm the existence of a shoulder in the short-range region of the Coulomb hole of the Ne atom, which is due to an internal reorganization of the $K$-shell caused by electron correlation of the core electrons. The feature is very sensitive to the quality of the basis set in the core region and it is not exclusive to Ne, being also present in most of second-row atoms, thus confirming that it is due to $K$-shell correlation effects.

physics.chem-ph↗

arXiv2016

Exact Exchange-Correlation Functional for the Infinitely Stretched Hydrogen Molecule

The exchange-correlation hole density of the infinitely stretched (dissociated) hydrogen molecule can be cast into a closed analytical form by using its exact wave function. This permits to obtain an explicit exchange-correlation energy functional of the electron density which allows for its functional derivation to yield the corresponding Kohh-Sham effective exchange-correlation potential. We have shown that this exchange-correlation functional is exact for the dissociated hydrogen molecule, yields its dissociation energy correctly, and its corresponding exchange-correlation potential has the correct $-1/r$ asymptotic behavior.

physics.chem-ph↗