22 research outputs found
Understanding highly excited states via parametric variations
Highly excited vibrational states of an isolated molecule encode the
vibrational energy flow pathways in the molecule. Recent studies have had
spectacular success in understanding the nature of the excited states mainly
due to the extensive studies of the classical phase space structures and their
bifurcations. Such detailed classical-quantum correspondence studies are
presently limited to two or quasi two dimensional systems. One of the main
reasons for such a constraint has to do with the problem of visualization of
relevant objects like surface of sections and Wigner or Husimi distributions
associated with an eigenstate. This neccesiates various alternative techniques
which are more algebraic than geometric in nature. In this work we introduce
one such method based on parametric variation of the eigenvalues of a
Hamiltonian. It is shown that the level velocities are correlated with the
phase space nature of the corresponding eigenstates. A semiclassical expression
for the level velocities of a single resonance Hamiltonian is derived which
provides theoretical support for the correlation. We use the level velocities
to dynamically assign the highly excited states of a model spectroscopic
Hamiltonian in the mixed phase space regime. The effect of bifurcations on the
level velocities is briefly discussed using a recently proposed spectroscopic
Hamiltonian for the HCP molecule.Comment: 12 pages, 9 figures, submitted to J. Chem. Phy
Application of Wire Grid Structures for Broadbanding of Monolithic Radomes
Abstract attached as PD
Wire Compensated A-Sandwich Radome for Aerospace Applications
Abstract attached as PD
Properties of chemically modified gelatin films
Edible and/or biodegradable films usually have limited water vapor barriers, making it difficult to use them. Thus, the objective of this work was to evaluate the effect of a chemical reticulation treatment with formaldehyde and glyoxal on the mechanical properties, water vapor permeability, solubility and color parameters of gelatin-based films. Formaldehyde and glyoxal were added to the filmogenic solution in concentrations ranging from 3.8 to 8.8 mmoles/100 mL of filmogenic solution and 6.3 to 26.3 mmoles/100 mL of filmogenic solution, respectively. The treatments caused a reduction in permeability to water vapor and in solubility. Only the treatment with formaldehyde caused a significant increase in rupture tension for concentrations above 6.3 mmoles/100 mL of filmogenic solution. Scanning electron microscopy indicated a loss of matrix orientation due to the chemical reticulation treatment