Gagan B. Pradhan

Ultracold collisions of O(1D) and H2: the effects of H2 vibrational excitation on the production of vibrationally and rotationally excited OH.

A quantum dynamics study of the O((1)D) + H2(v = 0 - 2, j = 0) system has been carried out using the potential energy surfaces of Dobbyn and Knowles [Mol. Phys. 91, 1107 (1997)]. A time-independent quantum mechanical method based on hyperspherical coordinates is adopted for the dynamics calculations. Energy dependent cross section, probability, and rate coefficients are computed for the elastic, inelastic, and reactive channels over collision energies ranging from the ultracold to thermal regimes and for total angular momentum quantum number J = 0. The effect of initial vibrational excitation of the H2 molecule on vibrational and rotational populations of the OH product is investigated as a function of the collision energy. Comparison of results for vibrational levels v = 0 - 2 of H2 demonstrates that the vibrational excitation of H2 and its non-reactive relaxation pathway play a minor role in the overall collisional outcome of O((1)D) and H2. It is also found that while the state-resolved product vibrational distributions are sensitive to the initial collision energy and H2 vibrational level, the product rotational distribution depicts an inverted population that is largely insensitive to initial conditions. Rate coefficients evaluated using a J-shifting approximation show reasonable agreement with available theoretical and experimental results suggesting that the J-shifting approximation may be used to evaluate the rate coefficients for O((1)D) + H2 reaction.

Pronounced effects of interchannel coupling in high-energy photoionization

The 3d core level photoemission of metallic Ag and In was measured over a wide energy range including the 2p ionization thresholds. The intensities (photoionization cross sections) of the 3d5/2 and 3d3/2 lines were observed to modulate significantly with photon energy, both absolute and relative, and this is most pronounced in the vicinity of the 2p thresholds, i.e., at photon energies about an order of magnitude above the 3d thresholds. Calculations based on the relativistic-random-phase approximation show that this effect is due to interchannel coupling of the 3d photoionization channels with the 2p channels affecting the cross section over a wide range of energies. It is argued that this is a general phenomenon in high-energy photoionization throughout the periodic table.

Ultracold chemistry with alkali-metal-rare-earth molecules

A first principles study of the dynamics of

Quantum dynamics of O(1D)+D2 reaction: isotope and vibrational excitation effects

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Cooper minima: a window on nondipole photoionization at low energy

Li(

Photodetachment cross section of lithium negative ion

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Photoionization of the 2p subshell in the Ar isonuclear sequence

S) +

Photoionization of Ca 4s in a spherical attractive well potential: dipole, quadrupole and relativistic effects

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Photoionization of the 5s subshell of Ba in the region of the second Cooper minimum: cross sections and angular distributions

Li

Dipole and quadrupole photodetachment/photoionization studies of the Ar isoelectronic sequence

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