Semiclassical calculations of collision line broadening in Raman spectra of N2 and CO mixtures

We present a detailed theoretical study of pressure-broadened Raman line shapes in binary mixtures of nitrogen and carbon monoxide. The semiclassical Robert-Bonamy theory was used to calculate self-broadened Q-branch linewidths of N(2) and CO, and Lennard-Jones (LJ) potential energy surface parameters were fixed by comparing our results with extensive experimental linewidth data. For the case of N(2), the ab initio PES8 potential energy surface was investigated, however, the anisotropic repulsive part had to be reduced to ensure a good agreement with experimental linewidths. The agreement between calculations and experiments was remarkably good, both for self-broadened N(2) and CO Q-branch linewidths. Yet, our calculations were not able to predict the experimentally observed difference between Q- and S-branch linewidths of self-broadened N(2). The central results of this work are the Q-branch linewidths of N(2)-CO and CO-N(2), which have been calculated through an extrapolation of the parameters of the potential energy surfaces used for self-broadened linewidths by common combination rules.     

Optimized interactions for targeted self-assembly: application to a honeycomb lattice

We devise an inverse statistical-mechanical methodology to find optimized interaction potentials that lead spontaneously to a target many-particle configuration. Target structures can possess varying degrees of disorder, thus extending the traditional idea of self-assembly to incorporate both amorphous and crystalline structures as well as quasicrystals. For illustration purposes, our computational technique is applied to yield an optimized isotropic (nondirectional) pair potential that spontaneously yields the three-coordinated honeycomb lattice as the ground state structure in two dimensions. This target choice is motivated by its three-dimensional analog, the diamond lattice, which is known to possess desirable photonic band gap properties.     

Self assembly,structure and properties of the decanuclear lanthanide ring complex,Dy10(OC2H4OCH3)30

Self assembly produced high yields of the lanthanide ring complex Dy10(OC2H4OCH3)30, the largest lanthanide ring known, characterized by X-ray diffraction methods and by magnetic susceptibility as a function of temperature.     

First synthesis of etidronate partial amides starting from PCl3

Methods for the preparation of mixed tetra-amide esters 1 and 2, the partial amide ester 3, and tri- and P,P-diamides 4 and 5 from monophosphorus spieces 12, 8 and 9, respectively, were developed. Compounds 8 and 9 were obtained from phosphorus trichloride via MeOPCl2, which was treated with 2 eq. and 4 eq. of piperidine, followed by water or acetyl chloride, respectively. Tetrasubstituted amide bisphosphonates 1 and 2 were selectively dealkylated with lithium or silyl halide to achieve target compounds 3-5. Piperidine was found to be a good desilylation reagent. Quantum mechanical calculations illustrate why derivative 2 was produced in low yield. The usefulness of compounds 1, 3 and 4 as prodrugs of etidronate was determined in aqueous buffer and human serum.     

Nonadiabatic alignment of asymmetric top molecules: field-free alignment of iodobenzene

Nonadiabatic laser alignment of an asymmetric top molecule is studied using the combination of a quantum dynamical theory and time-resolved photofragment imaging experiments. In particular, the degree of alignment of iodobenzene, induced by an intense, linearly polarized picosecond laser pulse, is calculated and measured. Pronounced alignment is obtained under field-free conditions.     

Dynamics of water in molecular sieves by dielectric spectroscopy

A short review of our thermodynamic and structural work on Ar, N₂, CO, O₂, and the n-alkane C₁₉H₄₀ in mesoporous glasses is presented. The experimental information comes from X-ray diffraction, vapour pressure isotherms, optical transmission, heat capacity, and dielectric measurements. The filling in the pore centre formed by capillary condensation is distinguished from the adsorbed layers on the pore walls and is compared to the bulk state. Special attention is paid to metastable states and to the rearrangement of partial fillings that show up as a consequence of phase transitions.Received: 1 January 2003, Published online: 21 October 2003PACS: 61.43.Gt Powders, porous materials - 78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures - 75.75. + a Magnetic properties of nanostructures - 77.22.-d Dielectric properties of solids and liquids     

Robustness of Objective and Subjective Speckle Patterns in the Speckle Strain Gauge

The robustness to rigid body object motions of three optical systems used in the speckle strain gauge were experimentally investigated and compared with analytical results of the correlation. It was found that an out-of-plane motion of the object damaged the reliability of the strain measure when recording the objective speckle patterns while subjective speckle patterns were more robust. Besides out-of-plane object motions, the robustness of a free-space geometry and an afocal imaging configuration are approximately the same, while a telecentric imaging system is more robust to rigid body motions but more sensitive to deformation gradients (basically in-plane rotation and tilt). Results from a measurement of the relaxation in a lead-tin alloy used in organ pipes is also presented.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27-29, Wako, Saitama, Japan.     

Rigorous solution of linear programming problems with uncertain data

This note gives a synopsis of new methods for solving linear systems and linear programming problems with uncertain data. All input data can vary between given lower and upper bounds. The methods calculate very sharp and guaranteed error bounds for the solution set of those problems and permit a rigorous sensitivity analysis. For problems with exact input data in general the calculated bounds differ only in the last bit in the mantissa, i.e. they are of maximum accuracy. This is a written account of an invited lecture delivered by the second author on occasion of the 14. Symposium über Operations Research, Ulm, 6.–8.9.1989.