Nonradiative relaxation and quantum beats in the radiative decay dynamics of large molecules

Journal Article · Thu Jan 06 04:00:00 EST 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100224a011· OSTI ID:6001432

Rhodes, W

The theory of photon emission is discussed for the case in which a molecule is excited by a coherent light pulse of frequency width ..delta.. omega corresponding to a few wavenumbers, or less, and bracketing a number of excited molecular eigenstates. Features of the theory which are considered include: (1) conditions whereby the time evolution of a frequency-resolved emission spectrum may be measured; (2) the nature of quantum beats and the importance of distinguishing quantum beats and oscillations due to quantum mechanical memory effects; (3) the importance of molecular emission channels and their doorway states for radiative decay as a practical (as well as conceptual) basis for understanding excited state dynamics; and (4) the effects of adiabatic modulation of the spectrally active modes of a molecule by the background modes of the molecule and its medium. The role of adiabatic modulation is the most important and far-reaching aspect of the present theory. We consider, in particular, the stochastic modulation (SM) limit of adiabatic modulation which is defined under certain conditions of fast modulation by weak coupling to many background modes. In addition to its effects on kinetic stabilization of quantum transitions and on the tuning of kinetic pathways of molecular processes, SM can erase the undesirable oscillations in photon emission, thereby permitting the emergence of quantum beats in the absence of frequency-resolvable spectral structure.

• Research Organization: Florida State Univ., Tallahassee, FL
• DOE Contract Number: AS05-78EV05784
• OSTI ID: 6001432
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:1; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
COHERENT RADIATION
DATA
DE-EXCITATION
ELECTROMAGNETIC RADIATION
ELECTRONIC STRUCTURE
EMISSION
EMISSION SPECTRA
ENERGY LEVELS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FREQUENCY DEPENDENCE
INFORMATION
KINETICS
MECHANICS
MOLECULES
NUMERICAL DATA
PHOTON EMISSION
POLYATOMIC MOLECULES
QUANTUM MECHANICS
RADIATIONLESS DECAY
RADIATIONS
REACTION KINETICS
RELAXATION
SPECTRA
THEORETICAL DATA
TIME DEPENDENCE