This thesis presents a study of the dynamics of trajectory calculations at low velocity utilizing potentials for the Li $_2$ -Ne and Li $_2$ -Xe collisional systems. We have found that at these low velocities, significant rovibrational energy transfer still takes place. This is due to the fact that there exists a ``capture radius'' at these low velocities such that if the impact parameter of the incoming atom is within this capture radius, the mutual attraction between the rare gas atom and Li $_2$ molecule is strong enough to force the atom into the potential well of the collisional system. The energy that the atom gains as it falls down this steep potential well, in addition to the fact that there are actually a multitude of collisions that take place while the atom is in the well, allow for the possibility of significant energy transfer. In addition, we elucidate how changes in the initial vibrational and rotational quantum number affect the dynamics of this energy transfer. Finally, the fact that these low initial velocities correspond to ultra-cold temperatures suggest the possibility that these results can be tested experimentally in a device such as a magento-optical trap.This thesis presents a study of the dynamics of trajectory calculations at low velocity utilizing potentials for the Li$_2$-Ne and Li$_2$-Xe collisional systems. We have found that at these low velocities, significant rovibrational energy transfer still takes place. This is due to the fact that there exists a ``capture radius'' at these low velocities such that if the impact parameter of the incoming atom is within this capture radius, the mutual attraction between the rare gas atom and Li$_2$ molecule is strong enough to force the atom into the potential well of the collisional system. The energy that the atom gains as it falls down this steep potential well, in addition to the fact that there are actually a multitude of collisions that take place while the atom is in the well, allow for the possibility of significant energy transfer. In addition, we elucidate how changes in the initial vibrational and rotational quantum number affect the dynamics of this energy transfer. Finally, the fact that these low initial velocities correspond to ultra-cold temperatures suggest the possibility that these results can be tested experimentally in a device such as a magento-optical trap.

Jan 1, 20160 citations

Rovibrationally Inelastic Collisions of Ultracold Lithium Dimer

William Jasmine, Brian A. Stewart

Bulletin of the American Physical SocietyMay 25, 20160 citations

Inelastic collisions in ultracold gases confined by one-dimensional optical lattices

Zhiying Li

We present a formalism for rigorous multichannel scattering calculations of cross sections for inelastic collisions of atoms and molecules confined in one-dimensional optical lattices. We obtain analytical expressions for the mean frequency of inelastic collisions in a confined gas in the temperature regime $T~\ensuremath{\hbar}\ensuremath{\omega}$ and at temperatures $T\ensuremath{\gg}\ensuremath{\hbar}\ensuremath{\omega}$, where $\ensuremath{\omega}$ is the oscillation frequency of trapped particles in the confining potential. Our numerical calculations for the gaseous mixture of Li and Rb atoms show that inelastic collisions in the temperature regime $T~\ensuremath{\hbar}\ensuremath{\omega}$ exhibit a deviation from three-dimensional scattering. This deviation is more significant for systems with stronger confinement and larger scattering lengths. We find that the ratios of rate constants for inelastic scattering and elastic collisions are suppressed in confined gases at $T~\ensuremath{\hbar}\ensuremath{\omega}$, and this suppression is significant for Li-Rb collisions at $T<40$ $\ensuremath{\mu}$K.We present a formalism for rigorous multichannel scattering calculations of cross sections for inelastic collisions of atoms and molecules confined in one-dimensional optical lattices. We obtain analytical expressions for the mean frequency of inelastic collisions in a confined gas in the temperature regime $T~\ensuremath{\hbar}\ensuremath{\omega}$ and at temperatures $T\ensuremath{\gg}\ensuremath{\hbar}\ensuremath{\omega}$, where $\ensuremath{\omega}$ is the oscillation frequency of trapped particles in the confining potential. Our numerical calculations for the gaseous mixture of Li and Rb atoms show that inelastic collisions in the temperature regime $T~\ensuremath{\hbar}\ensuremath{\omega}$ exhibit a deviation from three-dimensional scattering. This deviation is more significant for systems with stronger confinement and larger scattering lengths. We find that the ratios of rate constants for inelastic scattering and elastic collisions are suppressed in confined gases at $T~\ensuremath{\hbar}\ensuremath{\omega}$, and this suppression is significant for Li-Rb collisions at $T<40$ $\ensuremath{\mu}$K.

Physical Review AJan 14, 20102 citations

Ultracold Molecular Collisions

Jesús Pérez‐Ríos

Springer eBooksJan 1, 20200 citations

This thesis presents a study of the dynamics of trajectory calculations at low velocity utilizing potentials for the Li

_2

-Ne and Li

_2

-Xe collisional systems. We have found that at these low velocities, significant rovibrational energy transfer still takes place. This is due to the fact that there exists a ``capture radius'' at these low velocities such that if the impact parameter of the incoming atom is within this capture radius, the mutual attraction between the rare gas atom and Li

_2

molecule is strong enough to force the atom into the potential well of the collisional system. The energy that the atom gains as it falls down this steep potential well, in addition to the fact that there are actually a multitude of collisions that take place while the atom is in the well, allow for the possibility of significant energy transfer. In addition, we elucidate how changes in the initial vibrational and rotational quantum number affect the dynamics of this energy transfer. Finally, the fact that these low initial velocities correspond to ultra-cold temperatures suggest the possibility that these results can be tested experimentally in a device such as a magento-optical trap.

T<40

$\ensuremath{\mu}$K.