Publications by authors named "J M Charry"
We performed a computational study of positron attachment to hydrated amino acids, namely glycine, alanine, and proline in the zwitterionic form. We combined the sequential quantum mechanics/molecular mechanics (s-QM/MM) method with various levels of any particle molecular orbital (APMO) calculations. Consistent with previous studies, our calculations indicate the formation of energetically stable states for the isolated and microsolvated amino acids, in which the positron localizes around the carboxylate group.
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- The study investigates the stability and properties of complexes formed by halide anions and positrons using advanced computational methods to analyze their energetic configurations.
- Findings show that these positronic complexes are globally stable due to the formation of two-positron bonds, which contrasts with some less stable configurations like PsH that can easily emit positrons.
- The research also highlights similarities between two-positron dihalides and traditional two-electron dialkali molecules, suggesting notable trends in bonding properties, with the positron-containing complexes exhibiting unique characteristics such as shorter bond lengths and higher bond energies compared to their electron counterparts.
van der Waals Radii of Free and Bonded Atoms from Hydrogen (Z = 1) to Oganesson (Z = 118).
J Chem Theory Comput
September 2024
Reliable numerical values of van der Waals (vdW) radii are required for constructing empirical force fields, vdW-inclusive density functional, and quantum-chemical methods, as well as for implicit solvent models. However, multiple definitions exist for vdW radii, involving either equilibrium or the closest contact distances between free or bonded atoms within molecules or crystals. For the paradigmatic case of the hydrogen atom, its reported vdW radius fluctuates between 2.
View Article and Find Full Text PDFPositronium (Ps) exhibits the ability to form energetically stable complexes with atoms and molecules before annihilation occurs. In particular, F, a halogen, shows the highest reported positronium binding energy (2.95 eV) in the periodic table.
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- Researchers investigated how two positrons can help stabilize three hydride anions by forming unique bonds, highlighting the potential of positronic compounds.
- Their study involved advanced computational methods, including Multi-Component MP2 and Monte Carlo calculations, to explore the energy and stability of the 2e[H ] system.
- Findings revealed notable similarities between 2e[H ] and trilithium cation, supporting the idea of a new type of bonding in positronic molecules that differs from traditional electron-based bonds.