Microsolvation of electrons by a handful of ammonia molecules.

Microsolvation of electrons in ammonia is studied here via anionic NH clusters with n = 2-6. Intensive samplings of the corresponding configurational spaces using second-order perturbation theory with extended basis sets uncover rich and complex energy landscapes, heavily populated by many local minima in tight energy windows as calculated from highly correlated coupled cluster methods. There is a marked energetical preference for structures that place the excess electron external to the molecular frame, effectively coordinating it with the three protons from a single ammonia molecule.

Structure, energy, and bonding in anionic water tetramers obtained by exhaustive search.

An analysis of the structures, some energy related properties, and key aspects of the bonding nature of the microsolvated electron with four water molecules is presented. The study is based on an exhaustive potential energy surface scan of the ground state of (HO) at the UCCSD(T)/6-311(3+,4+)G(d,p)//UMP2/6-311(3+,4+)G(d,p) level. A total of 18 structures, most of them not reported before, spanning in an energy range of 8.

Exotic species with explicit noble metal-noble gas-noble metal linkages.

We present a study of the isoelectronic PtNgF and [AuNgF] species with noble gas atoms (Ng = Kr, Xe, Rn) acting as links bridging the two noble metal atoms. The stability of the species is investigated using several thermodynamic, kinetic and reactivity indicators. The results are compared against [AuXe], which is thermodynamically unstable in the gas phase but is stabilized in the solid state to the point that it has been experimentally detected as [AuXe](SbF) (S.

Spin-Orbit Coupling Effects in AumPtn Clusters (m + n = 4).

A study of AumPtn(m + n = 4) clusters with and without spin-orbit (SO) coupling using scalar relativistic (SR) and two component methods with the ZORA Hamiltonian was carried out. We employed the PW91 functional in conjunction with the all-electron TZ2P basis set. This paper offers a detailed analysis of the SO effects on the cluster geometries, on the LUMO-HOMO gap, on the charge distribution, and on the relative energies for each relativistic method.

Types and characteristics of drinking water for hydration in the elderly.

The role of hydration in the maintenance of health is increasingly recognized. Hydration requirements vary for each person, depending on physical activity, environmental conditions, dietary patterns, alcohol intake, health problems, and age. Elderly individuals have higher risk of developing dehydration than adults.