Vibrational spectroscopy of cis- and trans-formic acid in solid argon

Absorption spectra of cis and trans conformers of formic acid (HCOOH) isolated in solid argon are analyzed in the mid-infrared (4000-) and near-infrared (7800-) regions. The HCOOH absorption spectrum reveals matrix-site splitting for the trapped molecule. Narrowband tunable infrared radiation is used to pump a suitable vibrational transition of the trans conformer in order to promote site-selectively the conversion to the cis conformer and separate the spectral features of each site group. Several anharmonic resonances are identified for both conformers. The results of anharmonic vibrational ab initio calculations (CC-VSCF) for the trans and cis conformers of formic acid are reported and compared with the experimental spectra.     

Diffraction from phase modulated apertures

We apply the Rayleigh-Sommerfeld diffraction integral to solve the diffracted fields of periodically phase-modulated apertures. We show that the diffraction of small phase modulated apertures (with few refractive index modulation periods) behaves as for phase gratings, but the sharp diffraction peaks may already appear in the Fresnel region behind the aperture. Thus, these components may serve as lensless miniature interconnection gratings in micro-optics.     

UV-spectrophotometric determination of tetrazene

Ohne Zusammenfassung

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UV-spectrophotometric determination of tetrazene

     

Order preserving extendible hashing and bucket tries

A data model for the analysis of worst and expected case performance of order preserving address calculation type data structures is presented. This model is used to derive results on the storage costs ofm-arytrie structures. The binary trie structure (EXHASH) is shown to be optimal in many ways. Under quite general conditions the expected performance of bucket tries for generalized priority queue access operations is shown to be asymptotically optimal, i.e.O(1).     

Optical Implementation of Precise Color Classification Using Computer Controlled Set of Light Emitting Diodes

Accurate color classification by vector subspace method was implemented by simple optical system including computer controlled set of light-emitting diodes and a photo-receiver operating in the integration regime. The technique is capable for fast and precise classification of color distribution within two-dimensional frame with high spatial resolution. The feasibility of the proposed system is shown by a test of four metameric colors, which were correctly distinguished.     

Two-component heterogeneous nucleation kinetics and an application to Mars

We develop a two-component heterogeneous nucleation model that includes exact calculation of the Stauffer-type [D. Stauffer, J. Aerosol Sci. 7, 319 (1976)] steady-state kinetic prefactor using the correct heterogeneous Zeldovich factor for a heterogeneous two-component system. The model, and a simplified version of it, is tested by comparing its predictions to experimental data for water-n-propanol nucleating on silver particles. The model is then applied to water-carbon dioxide system in Martian conditions, which has not been modeled before. Using the ideal mixture assumption, the model shows theoretical possibilities for two-component nucleation adjacent to the initial stages of one-component water nucleation, especially with small water vapor amounts. The numbers of carbon dioxide molecules in the critical cluster are small in the case of large water amounts (up to 300 ppm) in the gas phase, but larger when there is very little water vapor (1 ppm).     

Arnowitt–Deser–Misner representation and Hamiltonian analysis of covariant renormalizable gravity

We study the recently proposed Covariant Renormalizable Gravity (CRG), which aims to provide a generally covariant ultraviolet completion of general relativity. We obtain a spacetime decomposed form—an Arnowitt–Deser–Misner (ADM) representation—of the CRG action. The action is found to contain time derivatives of the gravitational fields up to fourth order. Some ways to reduce the order of these time derivatives are considered. The resulting action is analyzed using the Hamiltonian formalism, which was originally adapted for constrained theories by Dirac. It is shown that the theory has a consistent set of constraints. It is, however, found that the theory exhibits four propagating physical degrees of freedom. This is one degree of freedom more than in Hořava–Lifshitz (HL) gravity and two more propagating modes than in general relativity. One extra physical degree of freedom has its origin in the higher order nature of the CRG action. The other extra propagating mode is a consequence of a projectability condition similarly as in HL gravity. Some additional gauge symmetry may need to be introduced in order to get rid of the extra gravitational degrees of freedom.     

Theoretical study of Rb2 in He(N): potential energy surface and Monte Carlo simulations

An analytical potential energy surface for a rigid Rb? in the 3Σ(u)? state interacting with one helium atom based on accurate ab initio computations is proposed. This 2-dimensional potential is used, together with the pair approximation approach, to investigate Rb? attached to small helium clusters He(N) with N = 1-6, 12, and 20 by means of quantum Monte Carlo studies. The limit of large clusters is approximated by a flat helium surface. The relative orientation of the dialkali axis and the helium surface is found to be parallel. Dynamical investigations of the pendular and of the in-plane rotation of the rigid Rb? molecule on the surface are presented.     

Single-layer one-dimensional nonpolarizing guided-mode resonance filters under normal incidence

We demonstrate that properly designed one-dimensional guided-mode resonance filters (GMRFs) with only one grating layer can exhibit a nonpolarizing resonant filtering effect under normal incidence. A sinusoidal profile nonpolarizing GMRF is realized by photoinduced surface-relief grating formation on thin films of polymer-azobenzene complexes and subsequent atomic layer deposition, showing the feasibility of fabrication of such compact GMRFs.