@misc{10481/49168,
year = {2018},
url = {http://hdl.handle.net/10481/49168},
abstract = {In this thesis we have theoretically investigated the electronic structure and properties of two
types of polyatomic Rydberg molecules, which differ on their binding mechanism.
We have first analyzed the impact of an external electric field on a triatomic Rydberg
molecule formed by a Rydberg rubidium atom and two ground state rubidium atoms in
three geometrical configurations: two collinear arrangements and a planar one. The binding
mechanism is based on the low-energy collisions between the Rydberg electron and the ground
state atoms. The electronic structure of these triatomic Rydberg molecules is described
within the Born-Oppenheimer approximation, and we have used the s- and p-wave Fermi
pseudo-potentials to describe the interaction between the Rydberg electron and each of the
ground state perturbers. The adiabatic potential curves and surfaces present an oscillatory
behaviour as the distance between the ground state atoms and the Rydberg ionic core
increases, which is due to the highly oscillatory character of the Rydberg electron wave
function. The potential wells of these electronic states are deep enough to accommodate
several vibrational levels where the triatomic Rydberg molecule can exist. We have shown
that the external electric field enhances the bound character of these adiabatic electronic
states.
In the second part of this dissertation, we have investigated polyatomic Rydberg molecules
formed by a rubidium Rydberg atom and one or two diatomic heteronuclear molecules, being
KRb our prototype system. The binding mechanism is due to the anisotropic scattering of the
Rydberg electron from the permanent electric dipole moment of the polar molecule. Within
the Born-Oppenheimer approximation, we have performed a realistic treatment of the internal
rotational motion of the diatomic molecules. For the triatomic Rydberg molecule, we have
explored the adiabatic electronic states evolving from the Rydberg manifolds Rb(n; l >= 3),
with increasing principal quantum number n, and from the Rydberg states Rb(26d), Rb(28s)
and Rb(27p). In all these cases, we have found oscillatory Born-Oppenheimer potentials,
with stable configurations, which can accommodate several vibrational bound levels. For
the pentaatomic Rydberg molecule, we have considered symmetric and asymmetric linear
configurations and have studied the metamorphosis of the Born-Oppenheimer potential curves
as the distances between the Rydberg core and the polar molecules increase. Our focus is on
the pentaatomic Rydberg molecule formed from the degenerate manifold Rb(n = 20, l >= 3)
and the Rydberg state Rb(23s) with ground and rotationally excited KRb diatomic polar
molecules, respectively. As in the triatomic Rydberg molecule, we have encountered stable
electronic states with potential wells possessing rich vibrational spectra. Since the polar
diatomic molecules are allowed to rotate within these polyatomic Rydberg molecules, we
have also analyzed the impact of the Rydberg-atom-induced electric field on their rotational
dynamics. We have shown that the directional properties of KRb strongly depend on the
Rydberg state and on the initial rotational state of KRb forming the ultra-long range molecule.
The polar molecule is signi cantly oriented and aligned if the Rydberg degenerate manifold
is involved or if KRb was initially in its rotational ground state.},
organization = {Tesis Univ. Granada. Programa Oficial de Doctorado en: Física y Matemáticas},
publisher = {Universidad de Granada},
keywords = {Estados de Rydberg},
keywords = {Moléculas poliatómicas},
keywords = {Moléculas diatómicas},
keywords = {Rubidio},
keywords = {Estructura electrónica},
keywords = {Sistemas de Hamilton},
keywords = {Sistemas dinámicos diferenciables},
title = {Ultralong-range polyatomic Rydberg molecules},
author = {Aguilera Fernández, Javier},
}