The rotational a-type sepctra of 15N-labeled diazirine,H2CN2

The rotational a-type spectra of isotopically enriched diazirine isotopomers, H₂¹²C¹⁴N¹⁵N and H₂¹²C¹⁵N₂, have been recorded in the region between 8 and 300 GHZ; the latter isotopomer has been observed for the first time. Using Watson's A-reduced Hamiltonian, the rotational constants and the quartic and some sextic centrifugal distortion constants have been determined for the ground vibrational states.     

Pulsed laser oscillation at 488.0 nm and 514.5 nm in an Ar-He Pseudospark discharge

Pulsed laser oscillation at the 488.0 and 514.5 nm transitions of Ar II was observed in an Ar-He pseudospark discharge. The time delay between current rise and laser pulse of the 488.0 nm line was 2.5 μs.     

Effect of a fluctuating phase mismatch on spatial solitons in quadratic media

We investigate the evolution of self-guided beams in a chi((2)) medium with a fluctuating phase mismatch between the fundamental wave and its second harmonic, as may occur in particular when the quasi-phase-matching technique is applied. We show that the fluctuations reduce the phase correlation and act as an effective loss to solitary waves.     

Die Bestimmung von Spuren von Quecksilber

Ohne Zusammenfassung     

Density functional self-consistent quantum mechanics/molecular mechanics theory for linear and nonlinear molecular properties: Applications to solvated water and formaldehyde

A combined quantum mechanics/molecular mechanics (QM/MM) method is described, where the polarization between the solvent and solute is accounted for using a self-consistent scheme linear in the solvent polarization. The QM/MM method is implemented for calculation of energies and molecular response properties including the calculation of linear and quadratic response functions using the density-functional theory (DFT) and the Hartree-Fock (HF) theory. Sample calculations presented for ground-state energies, first-order ground-state properties, excitation energies, first-order excited state properties, polarizabilities, first-hyperpolarizabilities, and two-photon absorptions strengths of formaldehyde suggests that DFT may in some cases be a sufficiently reliable alternative to high-level theory, such as coupled-cluster (CC) theory, in modeling solvent shifts, whereas results obtained with the HF wave function deviate significantly from the CC results. Calculations carried out on water gives results that also are comparable with CC calculations in accuracy for ground-state and first-order properties. However, to obtain such accuracy an exchange-correlation functional capable of describing the diffuse Rydberg states must be chosen.     

Service network design with management and coordination of multiple fleets

We present a new optimization model for the tactical design of scheduled service networks for transportation systems where several entities provide service and internal exchanges and coordination with neighboring systems is critical. Internal exchanges represent border crossings necessitating changes of vehicles, while the coordination with neighboring systems represents intermodal operations. For a given demand, the model determines departure times of the services such that throughput time of the demand in the system is minimized. The model is an extension of the design-balanced capacitated multicommodity network design model that we denote service network design with asset management and multiple fleet coordination to emphasize the explicit modeling of different vehicle fleets. Data from a real-world problem addressing the planning of new rail freight services across borders serves to illustrate the capabilities of the formulation. We analyze how synchronization with collaborating services and removal of border-crossing operations impact the throughput time for the freight. We identify a significant potential for system performance enhancement from synchronization among collaborating services for the problem studied.     

Sojourn times,manifolds with infinite cylindrical ends,and an inverse problem for planar waveguides

We prove that two particular entries in the scattering matrix for the Dirichlet Laplacian on ℝ × (−γ, γ) determine an analytic strictly convex obstacle . With an additional symmetry assumption, one entry suffices. Part of the proof is an integral identity involving an entry in the scattering matrix and a distribution related to the fundamental solution of the wave equation. This identity holds for general manifolds with infinite cylindrical ends. A consequence of this is a relationship between the singularities of the Fourier transform of an entry in the scattering matrix and the sojourn times of certain geodesics. Partially supported by NSF grant DMS 0500267.     

Designing new European rail freight services

We present an optimization model for design of transportation services, with a particular emphasis on how attention to service quality affects the design. The model is applied to a real-world case study where opportunities for new rail-based freight transportation services are explored. Fleet sizing is introduced to the service network design, because cost of acquiring locomotives is high, and inefficient resource utilization could result if fleet sizing is carried out a posteriori. The problem is a cross-border planning problem, introducing need for change of locomotives at borders, and separate fleets of locomotives thus have to be modelled. Demand in the system is characterized by various commodity groups with different service quality requirements. We propose a mixed integer programming model with a nonlinear objective function. The model finds the most profitable operations for the train operator when important service quality factors are accounted for.     

Overview of theoretical and computational methods applied to the oxygen-organic molecule photosystem

The challenges of using modern theoretical and computational tools to model the unique features of the oxygen-organic molecule photosystem are discussed from a historical and pedagogical perspective. This review is written for the novice, but the problems formulated should stimulate the expert.