Stable structures and minima energies of Ar n H 2 O (n ϭ 1-26) clusters are determined by carrying out a stochastic search method coupling to molecular dynamics calculations. A nonrigid intramolecular potential surface together with a pairwise-additive intermolecular potential are used. A growing pattern mechanism is described for the structures in the ground state and a solvation process is observed. Molecular relaxation effects are characterized and the second differences on the cluster binding energies are calculated. The relative stability of the structures is discussed and compared with previous theoretical results.

Although allogeneic PBSC transplant results in a faster hematopoietic engraftment, there was an increase in acute GVHD. There was no clear benefit in relapse rate and no evidence that transplantation with PBSC benefits patient survival in our institution.

Classical trajectories studies in Cartesian coordinates are applied toanalyze Coriolis coupling for the energy transfer in H 2 O ϩ Ar process. Vibrational energies equal to 50 kcal/mol and 100 kcal/mol for initial rotational temperatures in the range 298 -30,000 K are used as initial conditions. Initial translational temperatures for the incoming atom are selected in the same way. Effects of rotational and translational temperatures at different initial conditions are also investigated in the molecular vibrational relaxation process.

ABSTRACT:Cluster structures are discussed in a nonrigid analysis, using a modified minima search method based on stochastic processes and classical dynamics simulations. The relaxation process is taken into account considering the internal motion of the Cl 2 molecule. Cluster structures are compared with previous works in which the Cl 2 molecule is assumed to be rigid. The interactions are modeled using pair potentials: the Aziz and Lennard-Jones potentials for the Ar-Ar interaction, a Morse potential for the Cl-Cl interaction, and a fully spherical/anisotropic Morse-Spline-van der Waals (MSV) potential for the Ar-Cl interaction. As expected, all calculated energies are lower than those obtained in a rigid approximation; one reason may be attributed to the nonrigid contributions of the internal motion of the Cl 2 molecule. Finally, the growing processes in molecular clusters are discussed, and it is pointed out that the growing mechanism can be affected due to the nonrigid initial conditions of smaller clusters such as Ar n Cl 2 (n Յ 4 or 5), which are seeds for higher-order clusters.

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