Nature of molecular resonances

Journal Article · Thu Jul 08 04:00:00 EDT 1982 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100211a021· OSTI ID:6536938

Rhodes, W

The dynamics of quantum-mechanical processes in molecules is developed theoretically in terms of a subsystems approach in which the molecule and its environment are divided into a primary subsystem (set of modes) and a background subsystem. The key features of the theory are as follows: (1) a fundamental distinction between adiabatic and nonadiabatic modulation of the primary subsystem is recognized. The former leads to the definition of the sudden potential associated with the molecule-bath energy surfaces. The limit of fast adiabatic modulation is termed stochastic modulation, which is defined in terms of the sudden potential and leads to the pure dephasing component of the transverse (T/sub 2/) relaxation constant; (2) a molecular resonance is defined in terms of the adiabatic and nonadiabatic coupling of states of the composite system. The equation of motion of the reduced density operator for a resonance is obtained by use of an effective Hamiltonian and by reduction with respect to the background modes (bath); (3) a coupling strength ordering rule is established for a degenerate resonance, whereby the basis is provided for distinguishing oscillatory and monotonic decay dynamics. This involves both the longitudinal (dissipative) and transverse (stochastic) components of the damping matrix. A very important consequence is the existence of kinetic stabilization of the primary subsystem due to modulation by the background; and (4) the theory is extended to a multiresonance system for which a stochastic Liouville equation is developed. 4 figures.

• Research Organization: Florida State Univ., Tallahassee
• DOE Contract Number: AS05-78EV05784
• OSTI ID: 6536938
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 86:14; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
CHEMICAL REACTION KINETICS
CORRELATIONS
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EQUATIONS OF MOTION
EXCITATION
IONIZATION
KINETICS
LASER RADIATION
MATHEMATICAL MODELS
MECHANICS
MODULATION
MOLECULES
PARTIAL DIFFERENTIAL EQUATIONS
PHOTOIONIZATION
QUANTUM MECHANICS
RADIATIONS
REACTION KINETICS
STABILIZATION
STOCHASTIC PROCESSES
THERMODYNAMICS