Excited States

Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also describes how IVRET can decrease the anisotropy of the angular distribution of photo dissociating molecules that takes longer than the rotational period of disassociation. The third paper explains rotations and electronic decay by focusing on nonresonant light scattering, which is explained in the theory of radiationless transitions, when the exciting light source is included. The last paper shows how sub-Doppler techniques adapted from atomic physics can measure accurately dense rotational triplet structure and singlet-triplet couplings in high vibrational triplet levels. This book will prove helpful for researchers whose work involves physical chemistry or molecular chemistry and physicists involved in atomic or solid-state physics.

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Contributors
Contents of Previous Volumes
Rotational Involvement in Intramolecular Vibrational Redistribution
I. Introduction
II. Dispersed Emission from Mixed States
A. Casting the Framework
B. Recognition of State-Mixing through Dispersed Emission
C. Time Evolution
III. The Case for Rotational Involvement in IVR
A. Experimental Evidence
B. Estimates of Coupled Rovibronic Level Densities
IV. Mechanisms for Rotational Involvement in IVR
A. The Rotation-Vibration Hamiltonian
B. Relative Magnitudes of Terms in H
C. Quantum State Dependence of Coriolis and Centrifugal Terms
D. Vibrational State-Mixing through Coriolis and Centrifugal Coupling
E. The Passive Role of Rotations in Vibrational State-Mixing
V. Concluding Remarks
References
Intramolecular Vibration-Rotation Energy Transfer and the Orientational Dynamics of Molecules
I. Introduction
II. Theoretical Studies
III. Electric Deflection Experiments
IV. Laser-Induced Fluorescence Experiments
V. Conclusion
References
Rotations and Electronic Decay
I. Introduction
II. Rovibronic States
A. Rovibronic Hamiltonian
B. Rotational Wave Functions and the Pauli Principle
C. Intensities of Rovibronic Transitions
III. Excitation and Decay
A. General Theory
B. The Two Level Problem
C. Generalization to More States
D. Small, Intermediate, and Large Molecules
E. Nonresonant Light Scattering
F. Quantitative Treatment of NRLS and the Dependence of the Quantum Yield on Detuning
G. Selection Rules in Internal Conversion and Intersystem Crossing
IV. Experimental Results
A. Introduction
B. Benzene
C. The Azines
D. Summary
References
Singlet-Triplet Coupling in Small Organic Molecules by Anticrossing, Quantum Beat, and Magnetic Resonance Spectroscopy
I. Introduction
II. Principle of the Experiments
A. The Anticrossing (AC) Experiment
B. Optically Detected Magnetic Resonance Experiment
C. Quantum Beats Experiment
III. Structure Measurements
A. Rotational (ÄN) Selection Rule
B. Zeeman Degeneracy. Fine and Hyperfine Structure
C. Spectroscopy of the Triplet
D. Singlet-Triplet Coupling Hamiltonian
E. Vibrational Levels near the Bottom of the Triplet Well: Glyoxal
F. Vibrational Levels near a Dissociation Limit: Acetylene
IV. Dynamics of Singlet-Triplet Collisional Transfer in Glyoxal
A. Introduction
B. The Basic Ideas
C. Theory of I.S.C.
D. Experimental Checks and Discussion
V. Conclusions
Appendix A. Wavefunction Equations for Quantum Beats and Anticrossings
Appendix B. Magnetic Field Space Rotational Invariance Breaking
References
Index