Chapter 5 is devoted to energy transfer of translational, rotational, rovibronic,
and electronic excitation in collisions. The chapter focuses on so-called
collision-induced nonadiabatic transitions (CINATs), perturbation-facilitated, and
perturbation-irrelevant. Collision-induced nonadiabatic transitions between halogen
ion-pair states are discussed. A transfer of translational, rotational, and vibrational
energies in collisions are examined briefly. Electronic deactivation in which
collision-induced nonradiative transition to another electronic state, which occurs
with a large energy loss, is also discussed.
Weakly-bound, mainly van der Waals complexes and clusters (Chap. 6).
Halogen-containing complexes and clusters are examined in detail.
In the systems described in Chaps. 5 and 6, intermolecular perturbations of the
states occur in collisions of a species with a partner or optically populated
weakly-bound complexes of species. Intermolecular interactions occur in the gas
phase, liquids, solids, and polymers. These interactions are of great importance in
energy transfer processes in the gas phase, organization of structures, and properties
of biomolecules. Understanding the nature of intermolecular interactions is one of
the fundamental problems of modern chemical physics and molecular spectroscopy.
Van der Waals (vdW) complexes of free molecule excited states are ideal model
systems to predict the properties and dynamic behavior of more complex system.
The partners building the complex retain their identity, and energy transfers are thus
easily identified due to the weakness of the intermolecular noncovalent bond.
Investigation of the dependence of the energy redistribution and fragmentation
processes on the size of the cluster may help bridge the gap with condensed-phase
dynamics.
Collision-induced nonadiabatic transitions in the gas phase, in which vdW
complexes are formed in collisions and then decay, play a fundamental role in the
kinetics and dynamics of excited molecular electronic states. They are responsible
for radiative emission and energy transfer in the atmosphere, energy pooling and
conversion in laser media, relaxation phenomena in chemiluminescence processes,
plasma formation, and in many other situations where electronically excited states
are involved. Description of vdW complex formation and decay is essential for
understanding mechanisms of nonadiabatic transitions in weakly-bound complexes
of any molecules and clusters. Understanding of these processes is also necessary
for the interpretation and modeling of various photoinitiated processes in clusters,
liquids, and solids, where the role of intermolecular interaction is greatly magnified
through the formation of solvation shell(s) and multiple collisions between a
molecule and a solvent.
Mechanism and dynamics of vdW complex formation and decay are governed
by multidimensional potential energy surface (PES) of intermolecular interaction.
These data facilitate understanding the mechanism of interactions between specific
reagents and functions of intermolecular interactions in chemical processes.
Determination of propensity rules for vdW complex decay is necessary to develop a
description of dynamics in weakly-bound complexes.
2
1 Introduction
and electronic excitation in collisions. The chapter focuses on so-called
collision-induced nonadiabatic transitions (CINATs), perturbation-facilitated, and
perturbation-irrelevant. Collision-induced nonadiabatic transitions between halogen
ion-pair states are discussed. A transfer of translational, rotational, and vibrational
energies in collisions are examined briefly. Electronic deactivation in which
collision-induced nonradiative transition to another electronic state, which occurs
with a large energy loss, is also discussed.
Weakly-bound, mainly van der Waals complexes and clusters (Chap. 6).
Halogen-containing complexes and clusters are examined in detail.
In the systems described in Chaps. 5 and 6, intermolecular perturbations of the
states occur in collisions of a species with a partner or optically populated
weakly-bound complexes of species. Intermolecular interactions occur in the gas
phase, liquids, solids, and polymers. These interactions are of great importance in
energy transfer processes in the gas phase, organization of structures, and properties
of biomolecules. Understanding the nature of intermolecular interactions is one of
the fundamental problems of modern chemical physics and molecular spectroscopy.
Van der Waals (vdW) complexes of free molecule excited states are ideal model
systems to predict the properties and dynamic behavior of more complex system.
The partners building the complex retain their identity, and energy transfers are thus
easily identified due to the weakness of the intermolecular noncovalent bond.
Investigation of the dependence of the energy redistribution and fragmentation
processes on the size of the cluster may help bridge the gap with condensed-phase
dynamics.
Collision-induced nonadiabatic transitions in the gas phase, in which vdW
complexes are formed in collisions and then decay, play a fundamental role in the
kinetics and dynamics of excited molecular electronic states. They are responsible
for radiative emission and energy transfer in the atmosphere, energy pooling and
conversion in laser media, relaxation phenomena in chemiluminescence processes,
plasma formation, and in many other situations where electronically excited states
are involved. Description of vdW complex formation and decay is essential for
understanding mechanisms of nonadiabatic transitions in weakly-bound complexes
of any molecules and clusters. Understanding of these processes is also necessary
for the interpretation and modeling of various photoinitiated processes in clusters,
liquids, and solids, where the role of intermolecular interaction is greatly magnified
through the formation of solvation shell(s) and multiple collisions between a
molecule and a solvent.
Mechanism and dynamics of vdW complex formation and decay are governed
by multidimensional potential energy surface (PES) of intermolecular interaction.
These data facilitate understanding the mechanism of interactions between specific
reagents and functions of intermolecular interactions in chemical processes.
Determination of propensity rules for vdW complex decay is necessary to develop a
description of dynamics in weakly-bound complexes.
2
1 Introduction