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We report for the first time an accurate ab initio potential energy surface for the HeH+-H2system in four dimensions (4D) treating both diatomic species as rigid rotors. The computed ab initio potential energy point values are fitted using an artificial neural network method and used in quantum close coupling calculations for different initial states of both rotors, in their ground electronic states, over a range of collision energies. The state-to-state cross section results are used to compute the rate coefficients over a range of temperatures relevant to interstellar conditions. By comparing the four dimensional quantum results with those obtained by a reduced-dimensions approach that treats the H2molecule as an averaged, nonrotating target, it is shown that the reduced dimensionality results are in good accord with the four dimensional results as long as the HeH+molecule is not initially rotationally excited. By further comparing the present rate coefficients with those for HeH+-H and for HeH+-He, we demonstrate that H2molecules are the most effective collision partners in inducing rotational excitation in HeH+cation at interstellar temperatures. The rotationally inelastic rates involving o-H2and p-H2excitations are also obtained and they turn out to be, as in previous systems, orders of magnitude smaller than those involving the cation. The results for the H2molecular partner clearly indicate its large energy-transfer efficiency to the HeH+system, thereby confirming its expected importance within the kinetics networks involving HeH+in interstellar environments., Austrian Science Fund (FWF); Spanish Government (MINECO); Ministerio de Ciencia e Innovación (MCIN) / Agencia Estatal de Investigació (AEI) 10.13039/501100011033

This paper presents a comprehensive study on the effect of citric acid, sodium benzoate, sodium salicylate, and urea (hydrotropes) on the solubility and mass-transfer coefficient for the extraction of butyl acetate in water. The influence of a wide range of hydrotrope concentrations (0-3.0 mol/L) and different temperatures (303 K to 333 K) on the solubility of butyl acetate has been studied. The influence of different hydrotrope concentrations on the mass-transfer coefficient for the butyl acetate +water system has been ascertained. The Setschenow constant, K s , a measure of the effectiveness of hydrotrope, has been determined for each case. The solubility of butyl acetate increases with increase in hydrotrope concentration and also with temperature. Consequent to the increase in the solubility of butyl acetate, the mass-transfer coefficient was also found to increase with increase in hydrotrope concentration. A minimum hydrotrope concentration was found essential to show a significant increase in the solubility and mass-transfer coefficient for the butyl acetate + water system. The enhancement factor, which is the ratio of the value in the presence and absence of a hydrotrope, is reported for both solubility and mass-transfer coefficient.

The influence of a femtosecond laser pulse on an adsorbate molecule−metal surface system is investigated by considering a time-dependent coupling between the ground- and excited-state potential energy curves using the time-dependent quantum mechanical wave packet approach. It is shown that the probability of desorption is strongly dependent on the duration of the coupling and the image−charge attraction and that it increases with increase in vibrational excitation of the metal−adsorbate bond.

Extension a 3 dimensions de calculs anterieurs des spectres d'absorption des configurations de l'etat de transition H+H 2 →H 3 *→H 2 +H, la densite de H 3 * dans l'espace des configurations etant calculee a l'aide de trajectoires classiques 3D sur la surface de potentiel de Siegbahm-Liu-Truhlar-Horowitz