Effect of the cluster angular momentum J and the projectile orbital momentum L on capture probability and postcollision dynamics

Mella, Massimo 2009. Effect of the cluster angular momentum J and the projectile orbital momentum L on capture probability and postcollision dynamics. Journal of Chemical Physics 131 (12) , 124309. 10.1063/1.3239476

Preview

PDF - Published Version Download (1MB) | Preview

Abstract

In this work, collisions between rotating atomic clusters composed of Lennard-Jones (LJn) particles and an identical projectile have been investigated by means of trajectory simulations as a function of the cluster angular momentum J and internal energy E, and for different values of the projectile impact parameter b and relative velocity vp. As expected, the collision (Pc(b)) and capture [or sticking Ps(b)] probabilities are found to decay below unity for values of b larger than the average surface radius of the cluster, with dP/db being strongly dependent on vp. Both Pc(b) and Ps(b), however, appear to be largely insensitive to the modulus of the cluster angular momentum |J| and only weakly dependent on E for collisions involving target clusters with a lifetime τ>100 ps. The latter findings are interpreted as indicating the absence of strong changes in the structure of the target as a function of |J| and E. The comparison between the dissociation lifetime (τdyn) of the postcapture complexes (LJn+1∗) obtained continuing trajectories after monomer capture and the one computed from the fragmentation of statistically prepared clusters (τstat) supports the validity of a two-step capture-dissociation model; similarly, the comparison between the average amount of energy exchanged during trajectories (ΔEdyn) in the process LJn+LJ→LJn+1∗→LJn+LJ and the one predicted by statistical simulations (ΔEstat) suggests a fast statistical energy redistribution in the collisional complex even for very short τdyn (e.g., 40 ps). In the case of projectiles aimed at the edge of the cluster [(grazing collisions, Pc(b)<1]; however, the time elapsed between formal collision and dissociation, τcoll, is such that τcoll<τstat and the trajectories indicate the presence of ballistic dynamics and of a weak energy exchange (ΔEcoll<ΔEdyn, with ΔEcoll being the average energy exchanged during collisions). The relevance of these results to the study of gas phase nucleation and to the possibility of building a fully microcanonical framework for its description is discussed.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
Additional Information:	9 pp. Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/0021-9606/ (accessed 21/02/2014).
Publisher:	American Institute of Physics
ISSN:	0021-9606
Date of First Compliant Deposit:	30 March 2016
Last Modified:	08 May 2023 04:17
URI:	https://orca.cardiff.ac.uk/id/eprint/23836

Citation Data

Cited 5 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item