Engineering topics

Song, Zhang

Publications and source records attributed to Song, Zhang.

3 records

DOE OSTI2011

Direct imaging of the Fermi resonance interaction in para-difluorobenzene: A special insight into energy redistributions in the S{sub 1} low-energy regime

We have experimentally observed the dynamics of the Fermi resonance interaction in the S{sub 1} low-energy regime of para-difluorobenzene at +819 cm{sup -1} by femtosecond time-resolved photoelectron imaging technique. The Fermi resonance interaction is clearly demonstrated by the time dependence of the photoelectron spectra; furthermore, the corresponding photoelectron angular distributions (PADs) clearly reflect each Fermi component character of the resonance 5{sup 1}{center_dot}{center_dot}{center_dot}6{sup 2}. The oscillation period for the Fermi resonance is estimated to be less than 20 ps from the time behavior of the photoelectron spectra, which is very close to our calculated oscillation period value of 13.3 ps. Our results demonstrate the vibrational energy transfer between the two Fermi resonance components of 5{sup 1} and 6{sup 2}, suggestive of a special insight into the vibrational energy redistribution in the S{sub 1} low-energy regime of para-difluorobenzene.

74 ATOMIC AND MOLECULAR PHYSICS↗

DOE OSTI2011

High-resolution 3D profilometry with binary phase-shifting methods

This paper presents a novel pixel-level resolution 3D profilometry technique that only needs binary phase-shifted structured patterns. This technique uses four sets of three phase-shifted binary patterns to achieve the phase error of less than 0.2%, and only requires two sets to reach similar quality if the projector is slightly defocused. Theoretical analysis, simulations, and experiments will be presented to verify the performance of the proposed technique.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2011

Direct observation of field-free alignment of asymmetric molecules in excited states

The excited state dynamics of o-dichlorobenzene has been studied by femtosecond time-resolved photoelectron imaging. The lifetime of the first excited state S{sub 1} of o-dichlorobenzene was determined to be 482 {+-} 10 ps. Field-free nonadiabatic alignment of the o-dichlorobenzene on the first excited state S{sub 1} (with an asymmetry parameter k = 0.153) by a femtosecond laser pulse was observed via time-resolved photoelectron angular distributions. Rotational wave packet revivals on the S{sub 1} state of the typical asymmetric molecule o-dichlorobenzene at 296 ps has been measured.

74 ATOMIC AND MOLECULAR PHYSICS↗