Coverage Dependence of the Level Alignment for Methanol on TiO2_2(110)

Electronic level alignment at the interface between an adsorbed molecular layer and a semiconducting substrate determines the activity and efficiency of many photocatalytic materials. We perform $G_0W_0$ calculations to determine the coverage dependence of the level alignment for a prototypical photocatalytic interface: 1/2 and 1 monolayer (ML) intact and dissociated CH$_3$OH on rutile TiO$_2$(110). We find changes in the wavefunction's spatial distribution, and a consequent renormalization of the quasiparticle energy levels, as a function of CH$_3$OH coverage and dissociation. Our results suggest that the occupied molecular levels responsible for hole trapping are not those observed in the ultraviolet photoemission spectroscopy (UPS) spectrum. Rather, they are those of isolated CH$_3$O on the surface. We find the unoccupied molecular levels have either 2D character with weight above the surface at 1 ML coverage, or significant hybridization with the surface at 1/2 ML coverage. These results suggest the resonance observed in the two photon phooemission (2PP) spectrum arises from excitations to unoccupied "Wet electron" levels with 2D character.Comment: 8 pages, 5 figures, 1 tabl

A Two-Coordinate Nickel Imido Complex That Effects C−H Amination

An exceptionally low coordinate nickel imido complex, (IPr*)Ni═N(dmp) (2) (dmp = 2,6-dimesitylphenyl), has been prepared by the elimination of N_2 from a bulky aryl azide in its reaction with (IPr*)Ni(η^6-C_7H_8) (1). The solid-state structure of 2 features two-coordinate nickel with a linear C−Ni−N core and a short Ni−N distance, both indicative of multiple-bond character. Computational studies using density functional theory showed a Ni═N bond dominated by Ni(dπ)−N(pπ) interactions, resulting in two nearly degenerate singly occupied molecular orbitals (SOMOs) that are Ni−N π* in character. Reaction of 2 with CO resulted in nitrene-group transfer to form (dmp)NCO and (IPr*)Ni(CO)_3 (3). Net C−H insertion was observed in the reaction of 2 with ethene, forming the vinylamine (dmp)NH(CH═CH_2) (5) via an azanickelacyclobutane intermediate, (IPr*)Ni{N,C:κ^2-N(dmp)CH_2CH_2} (4)

Genetic Variation and Heritability Estimates of Quality Traits in Brassica napus L.

To quantify genotypic variability and heritability among 8 Brassica napus genotypes were evaluated at New Developmental Research Farm, The University of Agriculture Peshawar during 2010-11. Analysis of variance revealed significant differences (P?0.01) among Brassica napus genotypes for all the character studied except for oil content. Mean values showed that maximum for oil content (52.0 %) for genotype CH-4, protein content (22.6 %) for genotype PGRI-7, glucosinolate content (85.4 umolg-1) for genotype CH-4 and erucic acid content (59.2 %) for genotype CH-3. One the other hand, minimum mean values for genotype PGRI-7, oil content  (47.3 %) for genotype CH-1, protein content (18.4 %) for genotype CH-2, glucosinolate content (49.0 umolg-1) for genotype CH-2, erucic acid content (35.0 %) for genotype CH-2. In addition, high broad sense heritability estimates were observed for erucic acid content (0.90), glucosinolate content (0.53), protein content (0.45) and oil content (0.16). In conclusion, significant differences among Brassica napus genotypes indicated sufficient variability among the tested material to have an effective selection. The trend of heritability (moderate to high) in the present study indicates that there is more genetic control and selection should lead to quick improvement. Furthermore Genotype CH-2 surpassed other genotype in quality traits and could be used in future breeding program. Keywords: Brassica napus, variability, heritability, quality traits, oil conten

Investigation of the short-time photodissociation dynamics of trans-1-bromo-2-iodoethane in the A-band absorption

We have obtained resonance Raman spectra and absolute Raman cross section measurements at five excitation wavelengths within the A-band absorption for 1-bromo-2-iodoethane in cyclohexane solution. The resonance Raman spectra have most of their intensity in the fundamentals, overtones, and combination bands of six Franck-Condon active vibrational modes; the nominal CCI bend, C-I stretch, C-Br stretch, C-C stretch, CH 2 wag with the Br atom attached to the CH 2 group, and CH 2 wag with the I atom attached to the CH 2 group. The resonance Raman intensities and A-band absorption spectrum were simulated using a simple model and time-dependent wave packet calculations. The simulation results and normal mode descriptions were used to find the short-time photodissociation dynamics in terms of internal coordinate displacements. The A-band short-time photodissociation dynamics for trans-1-bromo-2-iodoethane show that the C-I, C-Br, and C-C bonds as well as the CCI, CCBr, HCC, ICH, and BrCH angles have significant changes during the initial stages of the photodissociation reaction. This indicates the photodissociation reaction has a large degree of multidimensional character and suggests that the bromoethyl photofragment receives substantial internal excitation in so far as the short-time photodissociation dynamics determines the energy partitioning. Comparison of our results for 1-bromo-2-iodoethane with the A-band short-time dynamics of iodoethane, 1-chloro-2-iodoethane, and 1,2-diiodoethane and the trends observed for their A-band absorption spectra suggest that both the C-I and C-Br bonds experience a noticeable amount of photoexcitation. © 1999 American Institute of Physics.published_or_final_versio

Spectroscopic identification of Y(C4H6) isomers formed by yttrium-mediated C-H bond activation of butenes

Y(C$_{4}$H$_{6}$) was observed from the reactions of laser-vaporized Y atom with 1-butene (CH$_{2}$=CHCH$_{2}$CH$_{3}$) and iso-butene (CH$_{2}$=C(CH$_{3}$)$_{2}$) in a pulsed molecular beam source, and its structural isomers were investigated with mass-analyzed threshold ionization spectroscopy combined with electronic structure calculations and spectral simulations. Y(C$_{4}$H$_{6}$) was identified as a five-membered metallacycle [Y(CH$_{2}$-CH=CH-CH$_{2}$)] from the Y + 1-butene reaction and a tetrahedral structure [YC(CH$_{2}$)$_{3}$] from the Y + iso-butene reaction. The metallacycle has a C$_{s}$ structure with Y binding to the two terminal carbon atoms, whereas the tetrahedron has C$_{3v}$ symmetry with Y binding to the tertiary carbon atom of trimethylenemethane. Both isomers have a doublet ground state with the highest molecular orbital being largely a Y 5s character. Ionization removes the metal based electron, and the resultant singlet ion has a similar structure to the neutral complex. However, the adiabatic ionization energy [46309(5) cm$^{-1}$] of the tetrahedron is considerably higher than that [43473(5) cm$^{-1}$] of the cyclic structure

Women, culture, and identity in Kate Chopin's 'The awakening' and Assia Djebar's 'Ombre sultane'

Thesis (M.A.) University of Alaska Fairbanks, 2000Beginning with the assumption that women of all cultures experience a conflict between their culturally prescribed gender roles and their individual sexual desires, I comparie the characters Edna Pontellier of Kate Chopin's 'The Awakening' with Isma and Hajila of Assia Djebar's 'Ombre Sultane.' Each woman undergoes a process of awakening body consciousness that leads to her first experience of desire, an essential link between physical and mental consciousness. The expression of female desire conflicts with prescribed cultural behavior. Each character also moves away from her family and cultural roots, thus assuring herself a necessary distance for rebellion against social standards. However, of all three women, only Isma from 'Ombre Sultane' is able to return to her community, successfully resolving the conflict between gender and individual desire.Introduction -- ch. 1. Edan Pontellier -- ch. 2. Isma -- ch. 3. Hajila -- Afterward -- Literature cited

Efeito das interações hiperconjugativas na constante de acoplamento ¹J CH da hexametilenotetramina e do adamantano: estudo teórico e experimental

The objective of this work was to determine the influence of hyperconjugative interactions on the ¹J CH coupling constant for hexamethylenetetramine (1) and adamantane (2). For this end, theoretical and experimental ¹J CH were obtained and hyperconjugative interactions were investigated using NBO. It was observed, theoretically and experimentally, that ¹J CH in 1 is 20 Hz larger than in 2, mainly due to the nN®s*C-H hyperconjugative interaction. This interaction occurs only in 1, with an energy of 9.30 kcal mol-1. It increases the s-character of the carbon atom in the C-H bond and the occupancy of the sigma*C-H orbital in (1)