Resonances and chaos in the collinear collision system (He, H2+) and its isotopic variants

Mahapatra, Susanta ; Sathyamurthy, N. ; Ramaswamy, Ramakrishna (1997) Resonances and chaos in the collinear collision system (He, H2+) and its isotopic variants Pramana - Journal of Physics, 48 (2). pp. 411-424. ISSN 0304-4289

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The collinear atom-diatom collision system provides one of the simplest instances of chaotic or irregular scattering. Classically, irregular scattering is manifest in the sensitive dependence of post-collision variables on initial conditions, and quantally, in the appearance of a dense spectrum of dynamical resonances. We examine the influence of kinematic factors on such dynamical resonances in collinear (He, H2+) collisions by computing the transition state spectra for collinear (He, HD+) and (He, DH+) collisions using the time-dependent quantum mechanical approach. The nearest neighbor spacing distributionP(s) and the spectral rigidity Δ3(L) for these resonances suggest that the dynamics is predominantlyirregular for collinear (He, HD+) and predominantlyregular for collinear (He, DH+). These findings are reinforced by a significantly larger "correlation hole" in ensemble averaged survival probability ≪P(t)≫ values for collinear (He, HD+) than for collinear (He,DH+). In addition we have also examined measures of classical chaos through the dependence of the final vibrational action,nf, on the initial vibrational phaseφi of the diatom, and Poincaré surfaces-of-section. They show that (He, HD+) collisions are partly chaotic over the entire energy range (0–2.78 eV) while (He, DH+) collisions, in contrast, are highly regular at collision energies below the classical threshold for reaction. Above the threshold, the scattering remains regular for initial vibrational states v=0 and 1 of DH+.

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Source:Copyright of this article belongs to Indian Academy of Sciences.
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Deposited On:01 Feb 2018 12:21
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