Photoinduced transformations in C60 films irradiated by femtosecond laser pulses

Photoinduced polymerization and photoinduced diffusion of molecular oxygen in thin C₆₀ films irradiated by femtosecond laser pulses are investigated. A comparison of the Raman scattering and absorbed energy spectra and the irradiation doses required to observe photopolymerization using continuous-wave radiation and femtosecond pulses shows that the efficiency of both photoinduced processes decreases considerably in the latter case. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 4, 320–325 (25 August 1998)     

Complexing effect of N-hydroxyphthalimides in the stereospecific polymerization of methyl methacrylate

A study was carried out on the effect of both the temperature of the reaction medium and structure of the initiator (N-hydroxyphthalimides) on the tacticity of the polymethyl methacrylate obtained under radical polymerization conditions. An increase in the amount of hydroxyl groups in the N-hydroxyphthalimide (NHPI) molecule leads to an increase in syndiotactic sequences in the macromolecule. The Fordham equation was used to calculate the differences in the activation enthalpies and entropies for addition in the iso and syndio positions in the presence of various N-hydroxyphthalimides. In all cases, formation of a syndiotactic polymer is favored.     

Determination of the Duration of a Mid-Infrared Single-Cycle Light Bullet from the Structure of Induced Plasma Channels or Color Centers

JETP Letters - A method based on recording of the light-field amplitude of the pulse in the spatial structure of induced plasma channels or tracks of color centers in a transparent dielectric is...