Electronic Excitation Of H2 By Electron Impact Using Soft Norm-conserving Pseudopotentials

We calculate electronic excitation cross sections for the b 3∑u + a 3∑g + c 3∏u, and d 3∏u states of H2 by electron impact. Our results were obtained with the Schwinger multichannel method with pseudopotentials and real potentials at the two-channel level of approximation. Pseudo-H atoms are used to generate H2 molecules with almost the same low-energy spectrum as the real molecules. We show that the dynamics of the electronic excitation process of the pseudomolecules by electron impact is very similar to the real case. Our results support the idea that pseudopotentials can be used to obtain reliable molecular electronic excitation cross sections by low-energy electron impact, confirming the expectations of previous studies with CH2O and HBr.54654355437Takatsuka, K., McKoy, V., (1981) Phys. Rev. A, 24, p. 2473(1984) Phys. Rev. A, 30, p. 1734Bettega, M.H.F., Ferreira, L.G., Lima, M.A.P., (1993) Phys. Rev. A, 47, p. 1111Natalense, A.P.P., Bettega, M.H.F., Ferreira, L.G., Lima, M.A.P., (1995) Phys. Rev. A, 52, pp. R1Bettega, M.H.F., Natalense, A.P.P., Lima, M.A.P., Ferreira, L.G., (1995) J. Chem. Phys., 103, p. 10566Rescigno, T.N., McCurdy, C.W., (1996) J. Chem. Phys., 104, p. 120Rescigno, T.N., (1996) J. Chem. Phys., 104, p. 125Hamann, D.R., Schlüter, M., Chiang, C., (1979) Phys. Rev. Lett., 43, p. 1494Christiansen, P.A., Lee, Y.S., Pitzer, K.S., (1979) J. Chem. Phys., 71, p. 4445Topp, W.C., Hopfield, J.J., (1973) Phys. Rev. B, 7, p. 1295Bachelet, G.B., Hamann, D.R., Schlüter, M., (1982) Phys. Rev. B, 26, p. 4199Bettega, M.H.F., Natalense, A.P.P., Lima, M.A.P., Ferreira, L.G., (1996) Int. J. Quantum Chem., 60, p. 821Goddard III, W.A., Hunt, W.J., (1974) Chem. Phys. Lett., 24, p. 464Kolos, W., Wolniewicz, L., (1965) J. Chem. Phys., 43, p. 2429Kolos, W., Wolniewicz, L., (1968) J. Chem. Phys., 48, p. 3672Browne, J.C., (1964) J. Chem. Phys., 40, p. 43Lee, M.T., Machado, L.E., Brescansin, L.M., Meneses, G.D., (1991) J. Phys. B, 24, p. 509Lima, M.A.P., Gibson, T.L., McKoy, V., Huo, W.M., (1988) Phys. Rev. A, 38, p. 4527. , and references cited therei

Electron Scattering From Molecules: Applications Of The Schwinger Multichannel Method To E--co And E--c2h 4 Collisions

To illustrate our recent efforts to obtain electronic excitation cross sections of molecules by electron impact, we present in this paper results for the X 1Σ a 3Π and A 1Π transitions of CO obtained with the Schwinger multichannel method. Our results are in good agreement with other theoretical calculations, although not so good when compared with experiments. We also discuss the importance of inclusion of polarization effects to obtain electronic excitation cross sections of some molecules through an example using the C2H4 molecule, which has a triplet state with a low-energy threshold. Finally, we present a very simple rule to estimate integral electronic excitation cross sections using the differential cross section (DCS) at 900, which can be useful to experimentalists using apparatus with difficulties to measure the DCS's at angles around 0 and 180 degrees. We show its efficiency for the present electronic excitation of the C2H4 molecule by electron impact. © 2007 IOP Publishing Ltd.881Garscadden, A., (1992) Z. Phys., 24 (2), pp. 97-99Boudaïffa, B., Cloutier, P., Hunting, D., Huels, M.A., Sanche, L., (2000) Science, 287 (5458), pp. 1658-1660Da Costa, R.F., Da Paixão, F.J., Map, L., (2004) J. Phys. B: At. Mol. Phys., 37 (6), pp. 129-L135Da Costa, R.F., Da Paixão, F.J., Map, L., (2005) J. Phys. B: At. Mol. Phys., 38 (24), pp. 4363-4378Da Costa, R.F., Map, L., (2006) Int. J. Quantum Chem., 106 (13), pp. 2664-2676Nonum Da Costa, R.F., Map, L., (2007) Phys. Rev., 75, p. 022705Sun, Q., Winstead, C., McKoy, V., Lima, M.A.P., (1992) J. Chem. Phys., 96 (5), pp. 3531-3535Rescigno, T.N., Schneider, B.I., (1992) Phys. Rev., 45 (5), pp. 2894-2902Takatsuka, K., McKoy, V., (1981) Phys. Rev., 24 (5), pp. 2473-2480Takatsuka, K., McKoy, V., (1984) Phys. Rev., 30 (4), pp. 1734-1740Chaudhuri, P., Varella Do, T.M.N., Carvalho, C.R.C., Map, L., (2004) Nucl. Instrum. Methods Phys. Res., 221, pp. 69-75Chaudhuri, P., Varella Do, T.M.N., Carvalho, C.R.C., Map, L., (2004) Phys. Rev., 69, p. 042703Lane, N.F., (1980) Rev. Mod. Phys., 52 (1), pp. 29-119Sun, Q.Y., Winstead, C., McKoy, V., (1992) Phys. Rev., 46 (11), pp. 6987-6994Morgan, L.A., Tennyson, J., (1993) J. Phys. B: At. Mol. Opt. Phys., 26 (15), pp. 2429-2441Lee, M.-T., MacHado, A.M., Fujimoto, M.M., MacHado, L.E., Brescansin, L.M., (1996) J. Phys. B: At. Mol. Opt. Phys., 29 (18), pp. 4285-4301Furlong, J.M., Newell, W.R., (1996) J. Phys. B: At. Mol. Opt. Phys., 29 (2), pp. 331-338Leclair, L.R., Trajmar, S., (1996) J. Phys. B: At. Mol. Opt. Phys., 29 (22), pp. 5543-5566Zetner, P.W., Kanik, I., Trajmar, S., (1998) J. Phys. B: At. Mol. Opt. Phys., 31 (10), pp. 2395-2413Trajmar, S., Szabo, A., Ostlund, N.S., (1989) Modern Quantum Chemistry: Introduction to Advanced Electronic Structure Theory, pp. 194-197Da Costa, R.F., Bettega, M.H.F., Lima, M.A.P., Van Veen, E.H., (1976) Chem. Phys. Lett., 41 (3), p. 540Asmis, K.R., Allan, M., (1997) J. Chem. Phys., 106 (17), pp. 7044-7046Da Costa, R.F., Bettega, M.H.F., Lima, M.A.P., Da Costa, R.F., Bettega, M.H.F., Lima, M.A.P.

Characterization And Sensory Preference Of Fermented Dairy Beverages Prepared With Different Concentrations Of Whey And Araticum Pulp

The objective of this study was to develop a fermented dairy beverage flavored with araticum pulp, assess its physicochemical characteristics, microbiological quality, and sensory preference by the consumer. Araticum pulp was prepared using two different methods: with or without bleaching (50 °C/5 minutes). Formulations of fermented dairy beverages consisting of whey (50%), standardized pasteurized milk (50%), and seven different concentrations of bleached araticum pulp (5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0% w/v) were prepared. In addition, seven formulations of fermented dairy beverage, without adding araticum pulp, and consisting of varying proportions of whey (40, 50, 60, 70, 80, 90, and 100%) were developed. In all formulations, thickeners/stabilizers were added. All araticum pulp samples (with and without bleach) and fermented dairy beverages (with and without araticum pulp) were analyzed for the relevant physicochemical properties: pH, titratable acidity, acidity of pulp, acidity of fermented beverage, moisture, ash, fat, protein, crude fiber, ascorbic acid, carbohydrates, total solids, and caloric values. Microbiological counts of coliforms at 35 °C and 45 °C in the pulp and beverage, and molds and yeasts and Salmonella sp. in the pulp were obtained. Additionally, sensory analysis regarding preferences of the different fermented dairy beverage formulations was also performed. The araticum pulp samples without bleach, showed higher values of pH, moisture, protein, total fiber, and ascorbic acid, as compared to bleached pulp samples, while bleached araticum pulp showed higher values for other physicochemical parameters. Microbiological results showed that all pulps and fruitdairy beverages were suitable for consumption. It was found that there was no significant consumer preference between different fermented beverage formulations, according to the different percentages of pulp. However, the formulations consisting of 40, 50, 60, and 70% whey were preferred over the one consisting of 100% whey.3764011402

Semi‐quantitative discrimination of honey adulterated with cane sugar solution by an ETongue

This study successfully applied a potentiometric E-tongue with 20 cross-selectivity lipidic polymeric membranes in the discrimination of three semi-quantitative groups, that represented the following intervals of honey adulteration percentage with cane sugar: 0 %; [0, 10]%; [10, 20]% of adulteration. We analysed five different types of Portuguese honey; five brands of cane sugar were added to the adulterated samples; a comparative analysis was then performed. Linear discriminant analysis coupled with a tabu search algorithm for feature selection was applied to the ETongue's analytical data to select the best model. A discriminant model with 12 sensors was obtained. This model classified correctly all samples in both in internal (train data, 15 samples) and external validation (test data,10 samples). Also, multiple linear regression with tabu search was applied to verify if ETongue's data would allow quantifying the honey's adulteration level. The results showed that it was possible to obtain a quantitative model but with unsatisfactory predictive performance in the test data group (external validation), giving, in general, values below the expected concentrations. E-tongue is a real-time green, flexible and low-cost analytical tool that requires minimum sample preparation and no special technical skills, being a promising tool for everyday application.This work was carried out in the course of ‘Electronic Tongue and Nose in Food Technology’ of the Master's degree in Food Technology of Universidade Tecnológica Federal do Paraná, Campo Mourão, Brasil. This study was financed in part by Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq, 308153/2018‐9) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior ‐ Brasil (CAPES) – Finance Code 001. The Portuguese authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for the financial support through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021).info:eu-repo/semantics/publishedVersio

Use of the electronic tongue as a tool for the characterization of Melipona scutellaris Latreille honey

This study aimed to characterize honey of Melipona scutellaris regarding its physicochemical parameters using the electronic tongue (e-tongue) technique combined with the multivariate statistical analysis for honey differentiation. Physicochemical parameters were evaluated following official methods of chemical analyses. A potentiometric electronic tongue with 16 cross-sensitivity sensors was used for the analysis. The Principal Component Analysis and the Cluster Analysis distinguished two groups for the sample set in the evaluation of physicochemical parameters, similar to results found using the electronic tongue. We verified a correlation greater than 0.70 between the profile of potentiometric signals and values of pH, ashes, electrical conductivity, HMF, diastase activity, reducing sugars, and apparent sucrose. The combined use of the electronic tongue with the statistical analysis showed the similarity between samples through the formation of two groups of the sample set. The electronic tongue may be used as a complement to traditional techniques of analyses to determine honey physicochemical parameters, constituting a promising tool in association with the multivariate statistical analysis.This study was financed in part by the “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil” (CAPES) - Finance Code 001 and by the “Fundação de Amparo à Pesquisa do Estado da Bahia” (FAPESB) - under grant PAM0004/2014. We thank “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq) for the scholarship granted to CALC (No. 305885/2017-0).info:eu-repo/semantics/publishedVersio

Ferromagnetism and Canted Spin Phase in AlAs/GaMnAs Single Quantum Wells: Monte Carlo Simulation

The magnetic order resulting from a confinement-adapted Ruderman-Kittel-Kasuya-Yosida indirect exchange between magnetic moments in the metallic phase of a AlAs/Ga(1-x)Mn(x)As quantum well is studied by Monte Carlo simulation. This coupling mechanism involves magnetic moments and carriers (holes), both coming from the same Mn(2+) ions. It leads to a paramagnetic, a ferromagnetic, or a canted spin phase, depending on the carrier concentration, and on the magnetic layer width. It is shown that high transition temperatures may be obtained.Comment: 7 figure