Anharmonicity contributions to the vibrational second hyperpolarizability of conjugated oligomers

Restricted Hartree-Fock 6-31G calculations of electrical and mechanical anharmonicity contributions to the longitudinal vibrational second hyperpolarizability have been carried out for eight homologous series of conjugated oligomers - polyacetylene, polyyne, polydiacetylene, polybutatriene, polycumulene, polysilane, polymethineimine, and polypyrrole. To draw conclusions about the limiting infinite polymer behavior, chains containing up to 12 heavy atoms along the conjugated backbone were considered. In general, the vibrational hyperpolarizabilities are substantial in comparison with their static electronic counterparts for the dc-Kerr and degenerate four-wave mixing processes (as well as for static fields) but not for electric field-induced second harmonic generation or third harmonic generation. Anharmonicity terms due to nuclear relaxation are important for the dc-Kerr effect (and for the static hyperpolarizability) in the σ-conjugated polymer, polysilane, as well as the nonplanar π systems polymethineimine and polypyrrole. Restricting polypyrrole to be planar, as it is in the crystal phase, causes these anharmonic terms to become negligible. When the same restriction is applied to polymethineimine the effect is reduced but remains quantitatively significant due to the first-order contribution. We conclude that anharmonicity associated with nuclear relaxation can be ignored, for semiquantitative purposes, in planar π-conjugated polymers. The role of zero-point vibrational averaging remains to be evaluated

The curvature of the conical intersection seam: an approximate second-order analysis

We present a method for analyzing the curvature (second derivatives) of the conical intersection hyperline at an optimized critical point. Our method uses the projected Hessians of the degenerate states after elimination of the two branching space coordinates, and is equivalent to a frequency calculation on a single Born-Oppenheimer potential-energy surface. Based on the projected Hessians, we develop an equation for the energy as a function of a set of curvilinear coordinates where the degeneracy is preserved to second order (i.e., the conical intersection hyperline). The curvature of the potential-energy surface in these coordinates is the curvature of the conical intersection hyperline itself, and thus determines whether one has a minimum or saddle point on the hyperline. The equation used to classify optimized conical intersection points depends in a simple way on the first- and second-order degeneracy splittings calculated at these points. As an example, for fulvene, we show that the two optimized conical intersection points of C2v symmetry are saddle points on the intersection hyperline. Accordingly, there are further intersection points of lower energy, and one of C2 symmetry - presented here for the first time - is found to be the global minimum in the intersection space

Second-order Møller-Plesset perturbation theory without basis set superposition error : II : open-shell systems

The basis set superposition error-free second-order MØller-Plesset perturbation theory of intermolecular interactions was studied. The difficulties of the counterpoise (CP) correction in open-shell systems were also discussed. The calculations were performed by a program which was used for testing the new variants of the theory. It was shown that the CP correction for the diabatic surfaces should be preferred to the adiabatic ones

Quadrennial Need Study Report on Highways, Roads, and Streets for Study Years 2002-2021, Second Annual Update, January 2004

Study report on highways, roads and streets for future years by Iowa Department of Transportation

Investigation of the State Insurance Division's Oversight of Clinton Memorial Cemetery & Funeral Home, Inc, 1999

Investigative report produced by Iowa Citizens' Aide/Ombudsman

Quarterly Census of Employment and Wages, Preliminary County Data, Second Quarter, 2004

Second Quarterly County information for Census of Employment & Wage, County

Quarterly Census of Employment and Wages, Preliminary Statewide Data, Second Quarter, 2004

Second Quarterly County information for Census of Employment & Wage, Statewide

Implementació i avaluació d'un programa dirigit a l'alfabetització de les mares amb infants estragers en la seva llengua i en català

El projecte « Teixint Cultures » és un projecte de recerca-acció comunitari que intenta promoure des de l’àmbit de l’educació d’adults, l’aprenentatge de la llengua catalana a partir dels recursos lingüístics que les mares d’origen africà tenen en la seva llengua familiar. El programa es porta a terme des d’una biblioteca pública infantil, i atén a mares d’origen immigrat amb fills menors de tres anys no escolaritzats al seu càrrec. Tot el projecte està vehiculat a partir dels contes infantils. De fet, intenta recuperar els contes de tradició oral provinents del continent africà per posteriorment elaborar materials educatius bilingües (en català i en les seves llengües) que es puguin utilitzar com a llibres educatius de consulta, tant per les biblioteques públiques com pels centres educatius. Els resultats s'agrupen entres àmbits a) descripció de les característiques metodològiques i organitzatives que han fet possible el projecte; b) impacte del projecte en les participants (aprenentatge del català, actituds, satisfacció i autoestima, pràctiques al voltant de la narració i la lectura de contes a la llar); i c) impacte del projecte a la biblioteca i al context local de la població de Salt. El futur del projecte es relaciona amb el Pla d'Entorn lligat amb l'establiment de relacions de continuïtat família-escola, implicació de les entitats i associacions de persones estrangeres i el tractament educatiu de la llengua familiar de l'alumnat.

Economic crisis and recovery: changes in second birth rates within occupational classes and educational groups

This study assesses the decline in second birth rates for men and women across different skill levels in transitional Russia. Changes within educational groups and occupational classes are observed over three distinct time periods: the Soviet era, economic crisis, and economic recovery. The most remarkable finding is the similarity in the extent second birth rates declined within educational groups and occupational classes during the economic crisis. Although further decline occurred in the recovery period, more variation emerged across groups.

Labeling Regulations and Segregation of First- and, Second-Generation Genetically Modified Products: Innovation Incentives and Welfare Effects, April 2005

We review some of the most significant issues and results on the economic effects of genetically modified (GM) product innovation, with emphasis on the question of GM labeling and the need for costly segregation and identity preservation activities. The analysis is organized around an explicit model that can accommodate the features of both first-generation and second-generation GM products. The model accounts for the proprietary nature of GM innovations and for the critical role of consumer preferences vis-à-vis GM products, as well as for the impacts of segregation and identity preservation and the effects of a mandatory GM labeling regulation. We also investigate briefly a novel question in this setting, the choice of “research direction”when both cost-reducing and quality-enhancing GM innovations are feasible.