Raman structural study of random olefin copolymers

In this work we present Raman study of random copolymers of ethylene and propylene with a number of α-olefins, and investigation of the relationships between the spectral characteristics of the Raman lines and the copolymer structural properties. For both the copolymers we observed rapid decrease in the crystallinity and conformational order as the content of the incorporated monomer increases

Phenomena of g-u symmetry-breakdown in HD

Phenomena associated with the breakdown of inversion symmetry in the HD molecule are reviewed and discussed. A distinction is made between three kinds of physical effects observed in HD spectra. The existence of a small electric dipole moment in the ground state gives rise to vibrational and pure rotational transitions following selection rules of electric dipole transitions. Coupling between electronic states of g and u symmetry occurs, which is associated with the appearance of forbidden lines in the electronic spectrum. This effect occurs predominantly at near coincidences between levels of opposite inversion symmetry and a recently observed example of strongly interacting states (H̄ ′

Femtosecond control of an elementary unimolecular reaction from the transition-state region

We present a simple example of temporal control of the evolving dynamics in a reactive system — a unimolecular reaction with two channels. Using three femtosecond pulses, a wave packet is prepared, probed, and intercepted in the transition-state region. The femtosecond control pulse intercepts the predissociative system at a fixed time and internuclear separation, both determined by the ‘window’ of the laser pulse. Experiments are performed on the NaI system which is a prototype for studies of elementary nuclear motion and reaction dynamics along two potentials, the covalent (Na + I) and the ionic (Na^+ + I^−) channels

Femtosecond control of an elementary unimolecular reaction from the transition-state region

We present a simple example of temporal control of the evolving dynamics in a reactive system — a unimolecular reaction with two channels. Using three femtosecond pulses, a wave packet is prepared, probed, and intercepted in the transition-state region. The femtosecond control pulse intercepts the predissociative system at a fixed time and internuclear separation, both determined by the ‘window’ of the laser pulse. Experiments are performed on the NaI system which is a prototype for studies of elementary nuclear motion and reaction dynamics along two potentials, the covalent (Na + I) and the ionic (Na^+ + I^−) channels