Vibrational energy relaxation of a diatomic molecule in a superfluid liquid helium nanodroplet. Influence of the nanodroplet size, interaction energy and energy gap

The influence of the nanodroplet size, molecule-helium interaction potential energy and v=1-v=0 vibrational energy gap on the vibrational energy relaxation (VER) of a diatomic molecule (X2) in a superfluid helium...

Electric Field Excitation Suppression in Cold Atoms

In this article, the atom excitation suppression is studied in two mechanisms. The first mechanism for excitation suppression is caused by an external DC electric field. The second mechanism is due to the energy shift caused by an electric field generated by free charges, which are created by ionizing atoms. The latter mechanism is known as the Coulomb blockade. Here, the Coulomb forces originate from ions created by ionizing atoms with a UV laser. The interaction, which causes the suppression, is treated theoretically as dipole–charge interactions. In the model, the charge is an ion, and the dipole is an atom. From measurements, we use 85Rb atoms. The valence electron and the ion core are the two poles of an electric dipole. The interaction potential energy between the ion and the atom is proportional to 1R2, and the frequency shift caused by this interaction is proportional to 1R4, where R is the distance between the ion and the dipole considered. This research is motivated by potential applications for quantum information storage, remote control, creating hot plasmas using cold atoms, as well as electronic devices.

Effect of Salts and Organic Osmolytes is Due to Conservative Forces

Background: The impression given in the literature was that the net interaction potential energy, V is the difference between columbic-columbic and total weaker interaction energies. It is proposed however, that in aqueous solution all particles with full formal charges and partial charge (dipoles) contribute to the total interaction as applicable to conservative field but not to the exclusion of hydrophobic interaction if applicable. Objectives: The objectives are 1) To theoretically elucidate the basis of the intermolecular interaction, 2) To show that effectiveness of an osmolyte which may include inorganic ion to force macromolecular, (un)folding, the m-value, is a function of the implicit mobility (or translational velocity) of the cosolute, 3) To link the m-value to conservative forces (or potential energies, V) and 4) Quantitate the values of V. Methods: A major theoretical investigation and experimentation using Bernfeld method. Results and Discussion: There were higher velocities of amylolysis with salt than without it in the presence of ethanol. The magnitude of the calculated V and energy equivalent of the entropic term were higher with higher concentration of ethanol unlike was the case with graphically determined values which were generally higher in magnitude than calculated values. The values of the calculated V and intermolecular distance were respectively higher in magnitude and longer with higher concentration of the salt. Conclusion: The attractive interaction between a macromolecule and a cationic counter ion is due to long ranged ion-ion interaction which ultimately enhances the effect of short ranged interaction. Higher salt concentration promotes long ranged interaction. The translational velocity of the solvent and cosolute has a role in the quantification of intermolecular distance. A mathematical relationship exists between m-value and - V (or 2 K.E.). The values of V can be calculated based on the derived equations.

Interaction potential energy surface between superatoms

Potential energy surface of superatoms associated with distance and angle.

Термомеханика деформаций в ангармоническом твердом теле

The macroscopic laws determining the temperature and deformations of an anharmonic solid body in a given external temperature force field have been stated in the form of the first thermodynamics law supplemented by equations of state of the body. The internal and free energies necessary for it are found from the statistical sum in which some of degrees of freedom determining the body shape are discharged from statistical averaging. These functions of state have been calculated up to the first order of the perturbation theory in the anharmonicity for the microscopic dynamic model of the body with the interatomic interaction potential energy given as a series in powers of atom coordinates. The classical region of high temperatures is considered.

A new (multi-reference configuration interaction) potential energy surface for H 2 CO and preliminary studies of roaming

We report a new global potential energy surface (PES) for H 2 CO, based on precise fitting of roughly 67 000 MRCI/cc-pVTZ energies. This PES describes the global minimum, the cis - and trans -HCOH isomers, and barriers relevant to isomerization, formation of the molecular (H 2 +CO) and radical (H+HCO) products, and the loose so-called roaming transition-state saddle point. The key features of the PES are reviewed and compared with a previous PES, denoted by PES04, based on five local fits that are ‘stitched’ together by switching functions (Zhang et al. 2004 J. Phys. Chem. A 108 , 8980–8986 ( doi:10.1021/jp048339l )). Preliminary quasi-classical trajectory calculations are performed at the total energy of 36 233 cm −1 (103 kcal mol −1 ), relative to the H 2 CO global minimum, using the new PES, with a particular focus on roaming dynamics. When compared with the results from PES04, the new PES findings show similar rotational distributions, somewhat more roaming and substantially higher H 2 vibrational excitation. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’.

The effect of dissipation on the torque and force experienced by nanoparticles in an AC field

We discuss the force and torque acting on spherical particles in an ensemble in the presence of a uniform AC electric field. We show that for a torque causing particle rotation to appear the particle must be absorptive. Our proof includes all electromagnetic excitations, which in the case of two or more particles gives rise to one or more resonances in the spectrum of force and torque depending on interparticle distance. Several peaks are found in the force and torque between two spheres at small interparticle distances, which coalesce to just one as the separation grows beyond three particle radii. We also show that in the presence of dissipation the force on each particle is nonconservative and may not be derived from the classical interaction potential energy as has been done in the past.