A survey of the forces acting on and in molecules and the relation of these forces to molecular spectroscopic investigations is presented. New results, both experimental and theoretical, are presented which demonstrate aspects of these forces. / The experimental results are the observation of quenching of tautomer fluorescence and normal phosphorescence of 7-azaindole H-bonded complexes in dipolar solvents. The former observation is obtained at room temperature and is observed when the concentration of an alcohol is varied with a fixed concentration of 7-axaindole in a hydrocarbon solvent. The latter observartion is obtained when solutions of 7-azaindole in dipolar solvents are cooled slowly as opposed to fast cooling with liquid nitrogen. These observations are attributed to local forces resulting from dipolar solvent cages around the H-bonded complexes. / The theoretical results are that, due to currents within molecules, the Hellmann-Feynman theorem fails at the 10-ppm level of accuracy. The general non-quantum-electrodynamical form of the non-electrostatic forces responsible for this failure is derived. The general results are applied to the molecule HD('+) for which the first-order perturbation theoretical correction due to these forces to the 1-0 vibrational transition energy for the ground electronic state is calculated. The value obtained is -0.072 cm('-1). This value agrees with the experimental minus theoretical energy difference obtained if the theoretical calculations neglects these forces. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0972. / Thesis (Ph.D.)--The Florida State University, 1980.

A general theory of spin relaxation developed by Fulton is applied to the problem of rotational relaxation of a dipole rotating in two dimensions. The model system is composed of a rotor with dipole moment (mu) at the center of a circular cavity in a continuous, infinite dielectric medium (heat bath). We write a quantum-mechanical Hamiltonian for the system which contains a term for free rotor motion and a bath-rotor interaction term. An equation of motion for the operators describing the rotor is developed using Heisenberg's equation of motion in conjunction with the theory of functionals. This equation is taken in the classical limit by assuming that the rotor's rotational spacing is small. We choose a simple form for the free motion time dependence of the classical rotor functions and thereby identify the rotor functions with the eigenfunctions of the Liouville operator. Through consideration of the bath-rotor interaction we find the relevant bath functions to be the bath's electric field components at the center of the cavity. The classical equation of motion which results from this process describes the time dependence of the probability distribution for the rotor's angular momentum. This equation resembles a Fokker-Planck equation with a diffusion coefficient which depends upon the angular momentum. We find that this coefficient is related to the fluctuations of the bath's electric field in the cavity. The equation of motion is solved numerically by finite differences. The solution, corresponding to relaxation of a small molecule from a high initial angular momentum state, shows a double-maximum or "bimodal" shape for intermediate momentum values before relaxing to the equilibrium Boltzman distribution. This behaviour is qualitatively similar to experimental time-dependent angular momentum distributions found by Polanyi and co-workers for hydrogen / halides formed in molecular beam reactions. We also derive and solve numerically an equation of motion for the orientational correlation function of the rotor. / Source: Dissertation Abstracts International, Volume: 42-06, Section: B, page: 2388. / Thesis (Ph.D.)--The Florida State University, 1981.

A theoretical method of analyzing dynamics of laser excitation of molecular systems is presented. We use the eigenstates and eigenenergies of an effective Hamiltonian to solve directly for the time development operator matrix elements. We analytically solve for the transition probability amplitude matrix elements for a two-level system. We compare these results with computer simulations as a check on our software. We then apply our method computationally to the study of; three-level system dynamics, interaction of a single state with a manifold of 16 states (in the 'picket fence' limit), interaction of two states through a common continuum, and laser excitation of a molecular system represented by six levels. We predict the possibility of observing several phenomena dependent on the radiative intensity; radiative decoupling of radiationless transitions, optically induced radiationless transitions, intensity dependent photo-chemistry, and optical pumping of phosphoresence. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0977. / Thesis (Ph.D.)--The Florida State University, 1980.

Source: Dissertation Abstracts International, Volume: 40-09, Section: B, page: 4317. / Thesis (Ph.D.)--The Florida State University, 1979.

Source: Dissertation Abstracts International, Volume: 40-11, Section: B, page: 5287. / Thesis (Ph.D.)--The Florida State University, 1979.

Source: Dissertation Abstracts International, Volume: 41-07, Section: B, page: 2631. / Thesis (Ph.D.)--The Florida State University, 1980.

Resonance Raman spectroscopy and cryoenzymology have been combined to study the structures of intermediates in the peroxidase and oxidase pathways of HRP. The intermediates compound I, II, and III, have been stabilized at subzero temperatures in buffered methanol solutions. Vibrational spectra of the heme group of compounds II and III have been obtained by excitation in the vicinity of the B and Q transitions of the heme. The resultant spectra contain bands whose frequencies reveal the structure and coordination properties of the heme group in each catalytic intermediate. A comparison of these results with those for Mb, particularly between oxy-Mb and Compound III, reveal substantial differences in the low frequency regions (200 to 800 cm('-1)) and small differences in the high frequency skeletal modes. / Comparing these differences to model compounds, especially the isotopically sensitive Fe-O(,2) mode at 570 cm('-1) in Mb and 559 cm('-1) in compound III, demonstrates that the functional differences between these two proteins lies in the disposition of the proximal imidazole relative to the heme plane. / Source: Dissertation Abstracts International, Volume: 45-11, Section: B, page: 3522. / Thesis (Ph.D.)--The Florida State University, 1984.

In the investigation of new excited state proton transfer molecules two novel species (3-hydroxypicolinamide and methyl 2-hydroxy-6-methylnicotinate) were observed to have prominent excited state proton transfer. These molecules, with the nitrogen in pyridine ring, have different characteristic proton transfer aspects from those molecules which exhibit "methylsalicylate" type proton transfer. The picosecond transient spectroscopy of these two compounds is discussed where the normal and tautomer species are characterized. In dealing with the role of solvents for the excited state proton transfer a new TSLE (two steps laser excitation) detecting system was applied in the ground state recovery time measurements for two excited state proton transfer compounds 3-hydroxyflavone and 7-hydroxyquinoline. From the results a general discussion of solvent effects for proton transfer is discussed. Finally a remarkable lasing action of 3-hydroxyflavone, the proton transfer laser, is addressed. The observation of excited state proton transfer tautomerization approaches an ideal 4-level laser system involving four different molecular electronic species in the separate electronic states, and constitutes a photo-induced chemical laser. The large red shift tautomer emission of 3-hydroxyflavone and lack of tautomer reabsorption make this molecule suitable for achieving dual frequency simultaneous stimulated emissions in the 3-hydroxyflavone/dye mixture that can be applied in several advanced laser techniques such as CARS (Coherent Antistoke Raman Spectroscopy). / Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0177. / Thesis (Ph.D.)--The Florida State University, 1985.

Source: Dissertation Abstracts International, Volume: 33-07, Section: B, page: 3019. / Thesis (Ph.D.)--The Florida State University, 1972.

Vinyl type polymers can form thermoreversible gels, precipitates and solution crystals in dilute to moderately dilute concentrations of suitable solvents. Although the thermoreversible gelation of the vinyl polymers has been extensively studied, no unifying principles have as yet emerged that establishes the underlying mechanism(s). In the present work an attempt has been made to develop the general underlying aspect of this problem by studying the gelation behaviour of a complete set of stereostructure of the vinyl polymer, in selected solvents using polystyrene as a model system. / Underlying this research has been the determination for each polymer-solvent pair, of the kinetics, pseudo phase diagrams, and thermodynamic properties of the gelation as well as that of the related precipitates and crystallites that are formed. The kinetic studies served as a guide for establishing the appropriate conditions for the study of gelation mechanism and the thermodynamic structural properties of the gels and other species that are formed. The results obtained showed that the mechanisms of the gel formation depends on the specific solvent used. Five different gelation mechanisms were identified, depending on the situation. One or several of these mechanisms could be operative with the same polymer-solvent system. It has been established where and why these mechanisms are operative in terms of the kinetics of the processes involved, the position of the binodial and the chain structure. / For those polymers that form gels by a crystallization mechanism, a polymorphic crystalline structure is observed quite often. An extensive study regarding the conditions for the emergence, the crystallographic structure and the stability of the polymorphic structure was performed. The reason for the polymorphism can now be shown to be a natural consequence of the crystallization kinetics and is not a requirement for the gel formation as has been hypothesized. / Source: Dissertation Abstracts International, Volume: 51-01, Section: B, page: 0230. / Major Professor: Leo Mandelkern. / Thesis (Ph.D.)--The Florida State University, 1989.