Srihari Keshavamurthy

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The phenomenon of intramolecular vibrational energy redistribution (IVR) is at the heart of chemical reaction dynamics. Statistical rate theories, assuming instantaneous IVR, predict exponential decay of the population with the properties of the transition state essentially determining the mechanism. However, there is growing evidence that IVR competes with(More)
A subset of the highly excited eigenstates of thiophosgene (SCCl2) near the dissociation threshold are analyzed using sensitive measures of quantum ergodicity. We find several localized eigenstates, suggesting that the intramolecular vibrational energy flow dynamics is nonstatistical even at such high levels of excitations. The results are consistent with(More)
Unimolecular dissociation dynamics of a model three degree of freedom triatomic molecule is studied in order to understand the mechanisms for deviations from statisticality. Performing a wavelet based time-frequency analysis of the dynamics allows for the dynamics to be followed on the network of nonlinear resonances, also called as the Arnold web. The(More)
We study dynamical tunneling in a near-integrable Hamiltonian with three degrees of freedom. Despite the absence of discrete symmetry we show that the mixing of near-degenerate quantum states is due to dynamical tunneling mediated by the nonlinear resonances in the classical phase space. Identifying the key resonances allows us to selectively suppress the(More)
The correlation between overlap intensities and level velocities has been introduced as a sensitive measure capable of revealing phase space localization. Previously applied to chaotic quantum systems, here we extend the theory to near-integrable and mixed quantum systems. This measure is useful in the latter cases because it has the ability to highlight(More)
We study the nature of highly excited eigenstates of strongly coupled multimode systems with three degrees of freedom. Attempts to dynamically assign the eigenstates using classical-quantum correspondence techniques poses a considerable challenge, due to both the number of degrees of freedom and the extensive chaos in the underlying classical phase space.(More)
We study the effect of an internal rotor on the classical and quantum intramolecular vibrational energy redistribution (IVR) dynamics of a model system with three degrees of freedom. The system is based on a Hamiltonian proposed by Martens and Reinhardt [J. Chem. Phys. 93, 5621 (1990)] to study IVR in the excited electronic state of para-fluorotoluene. We(More)
The aim of this work is to understand the influence of chaotic states in control problems involving strong fields. Towards this end, we numerically construct and study the strong field control landscape of a bichromatically driven double well. A novel measure based on correlating the overlap intensities between Floquet states and an initial phase space(More)