Laser flash photolysis studies of the production of the triplet state of the xanthene dye, rose bengal (RB), have been carried out. The reactions of this state with oxygen to form singlet oxygen and the superoxide anion radical have been observed and yields measured. Quenching of RB(T,) by oxygen leads to approximately 75% singlet oxygen and 20% superoxide. The reactivity of these species-RB(T,), O,('Ag) and Of-with four nucleotides and DNA have been determined. Only guanine residues showed any noticeable reaction at neutral pH. At higher pH guanine rate constants increased. The consequences to biological photodynamic processes are discussed.

operative and is the dominating mechanism for these systems. This additional stopping mechanism must be electronic interaction of the very reactive fluorine atoms with the carbon atoms to form chemical bonds, i.e., trapping in a product potential well. ConclusionsThe experimental results show that very thin layers of fluoropolymers can be prepared on the surfaces of hydrocarbon polymers through the use of controlled fluorine-containing ion beams. The reaction produces fluorocarbons with specific bonding environments, e.g., -CHFand -CF2-, rather than physically implanting the ions in nondiscrete environments. The specific fluorine environments appear to be insensitive to the type of unsaturated sites in the polymers used. Fluorination by mass-selected and non-mass-selected beams has shown that, at 1-keV kinetic energy, molecular ions are dissociated upon impact with the surface and the nascent fluorine atoms are the reactants. Consequently, the nature of the fluorine-carrying molecular ions used in the beam is significant only to the extent that the non-fluorine atoms in the beam may be deposited on the surface and block the reactive sites.

Abstract— An excimer of 1‐cyanonaphthalene is produced in homogeneous organic solvents and in micelle containing detergent solutions. From solvent effects in homogeneous solution it is concluded that the excimer is relatively polar (dipole moment ∼ 4D). From a comparison with emission from that observed in homogeneous solvents, it is concluded that 1‐cyanonaphthalene is solubilized mainly in the Stern Layer of sodium dodecyl sulfate (SDS) and hexadecyltrimethyl ammonium bromide (HDTBr) micelles. The influence of variation of detergent concentration on the excimer to monomer emission ratio and the influence of NaCl concentration on the excimer to monomer emission ratio have been determined. Excimer formation is shown to be a convenient method for determination of the Kraft point of SDS solutions.