Energy Dispersive X-ray Reflectivity Applied To The Study Of Thermal Stability Of Self-assembled Organic Multilayers: Results On Phosphonic Acids

The temperature evolution of self-assembled phosphonic acid multilayers was investigated by energy dispersive X-ray reflectivity and angular-resolved reflectivity. Energy dispersive measurements were performed in an experimental setup specially designed for the X-ray fluorescence beamline of the Brazilian Synchrotron Light Laboratory. It allows the precise monitoring of phase transitions observed in organic thin film and multilayer systems. The studied multilayers - obtained from dip coating of a solution of octadecylphosphonic acid - present different bilayer periodicities of 50 (straight bilayer) and 34 (tilted bilayer). Energy dispersive and angular-resolved data evidence re-organization of the lamellar ordering of octadecylphosphonic acid multilayers as a function of temperature. The energy dispersive technique presents many advantages over conventional methods such as short acquisition time, possibility to vary external parameters and high flux, making it suitable for light scatterers as polymers and other organic molecules. © 2011 Elsevier B.V. All rights reserved.16123-2425212525Klauk, H., (2010) Chem. Soc. Rev., 39, pp. 2643-2666Zschieschang, U., Ante, F., Schlörholz, M., Schmidt, M., Kern, K., Klauk, H., (2010) Adv. Mater., 22, pp. 4489-4493Rivest, J.B., Swisher, S.L., Fong, L.K., Zheng, H.I., Alivisatos, A.P., (2011) ACS Nano, 5, pp. 3811-3816Als-Nielsen, J., MacMorrow, D., (2001) Elements of Modern X-ray Physics, , Wiley ChichesterPietsch, U., Holy, V., Baumbach, T., (2004) High-Resolution X-ray Scattering: From Thin Films to Lateral Nanostructures, , Springer-Verlag New YorkMatsushita, T., Niwa, Y., Inada, Y., Nomura, M., Ishii, M., Sakurai, K., Arakawa, E., (2008) Appl. Phys. Lett., 92, pp. 0241031-0241033Mukherjee, M., Bhattacharya, M., Sanyal, M.K., Geue, Th., Grenzer, J., Pietsch, U., (2002) Phys. Rev. e, 66. , 061801-161801-1Bhattacharya, M., Mukherjee, M., Sanyal, M.K., (2003) J. Appl. Phys., 94, pp. 2882-2887Bodenthin, Y., Grenzer, J., Lauter, R., Pietch, U., Lehmann, P., Kurth, D.G., Möhwald, H., (2002) J. Synchrotron Radiat., 9, pp. 206-209Swalen, J.D., Allara, D.L., Andrade, J.D., Chandross, E.A., Garoff, S., Israelachvili, J., McCarthy, T.J., Yu, H., (1987) Langmuir, 3, pp. 932-950Sofos, M., Goldberger, J., Stone, D.A., Allen, J.E., Ma, Q., Wei-Wen Tsai, D.J.H., Lauhon, L.J., Stupp, S.I., (2009) Nat. Mater., 8, pp. 68-75Riepl, M., Mirskya, V.M., Novotnyb, I., Tvarozekb, V., Rehacekb, V., Wolfbeis, O.S., (1999) Anal. Chim. Acta, 392, pp. 77-84Mende, L.S., Fechtenkötter, A., Müllen, K., Moons, E., Friend, R.H., MacKenzie, J.D., (2001) Science, 293, pp. 1119-1122Aizenberg, J., Black, A.J., Whitesides, G.M., (1998) Nature, 394, pp. 868-871Chitre, K., Yang, Q., Salami, T.O., Oliver, S.R., Cho, J., (2005) J. Eletron. Mater., 34, pp. 528-533Sinapi, F., Julien, S., Auguste, D., Hevesi, L., Delhalle, J., Mekhalif, Z., (2008) Electrochim. Acta, 53, pp. 4228-4238Nie, H.-Y., Walzak, M.J., McIntyre, N.S., (2006) J. Phys. Chem. B, 110, pp. 21101-21108McClain, R.L., Breen, J.J., (2001) Lnagmuir, 17, pp. 5121-5124Rui, S.W., Viswanathan, R., Zasadzinski, J.A., Israelachvili, J.N., (1995) Biophys. J., 68, pp. 171-178Fontes, G.N., Malachias, A., Paniago, R.M., Neves, B.R.A., (2003) Langmuir, 19, pp. 3345-3349Nie, H.-Y., Walzak, M.J., McIntyre, N.S., (2002) Langmuir, 18, pp. 2955-295

Measurement of psi (2S) production cross-sections in proton-proton collisions at v s=7 and 13 TeV

The cross-sections of \u3c8(2 S) meson production in proton-proton collisions at s=13TeV are measured with a data sample collected by the LHCb detector corresponding to an integrated luminosity of 275pb-1. The production cross-sections for prompt \u3c8(2 S) mesons and those for \u3c8(2 S) mesons from b-hadron decays (\u3c8(2S)-from-b) are determined as functions of the transverse momentum, pT, and the rapidity, y, of the \u3c8(2 S) meson in the kinematic range 2<20GeV/c and 2.0 < y< 4.5. The production cross-sections integrated over this kinematic region are \u3c3(prompt\u3c8(2S),13TeV)=1.430\ub10.005(stat)\ub10.099(syst)\u3bcb,\u3c3(\u3c8(2S)-from-b,13TeV)=0.426\ub10.002(stat)\ub10.030(syst)\u3bcb.A new measurement of \u3c8(2 S) production cross-sections in pp collisions at s=7TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of 614pb-1. The integrated production cross-sections in the kinematic range 3.5<14GeV/c and 2.0 < y< 4.5 are \u3c3(prompt\u3c8(2S),7TeV)=0.471\ub10.001(stat)\ub10.025(syst)\u3bcb,\u3c3(\u3c8(2S)-from-b,7TeV)=0.126\ub10.001(stat)\ub10.008(syst)\u3bcb.All results show reasonable agreement with theoretical calculations

Measurement of the eta(c)(1S) production cross-section in p p collisions at root s=13TeV

Using a data sample corresponding to an integrated luminosity of 2.0 fb-1, collected by the LHCb experiment, the production of the \u3b7c(1 S) state in proton\u2013proton collisions at a centre-of-mass energy of s=13TeV is studied in the rapidity range 2.0 < y< 4.5 and in the transverse momentum range 6.5<14.0GeV. The cross-section for prompt production of \u3b7c(1 S) mesons relative to that of the J/ \u3c8 meson is measured using the pp\uaf decay mode and is found to be \u3c3\u3b7c(1S)/\u3c3J/\u3c8=1.69\ub10.15\ub10.10\ub10.18. The quoted uncertainties are, in order, statistical, systematic and due to uncertainties on the branching fractions of the J/\u3c8\u2192pp\uaf and \u3b7c\u2192pp\uaf decays. The prompt \u3b7c(1 S) production cross-section is determined to be \u3c3\u3b7c(1S)=1.26\ub10.11\ub10.08\ub10.14\u3bcb, where the last uncertainty includes that on the J/ \u3c8 meson cross-section. The ratio of the branching fractions of b-hadron decays to the \u3b7c(1 S) and J/ \u3c8 states is measured to be Bb\u2192\u3b7cX/Bb\u2192J/\u3c8X=0.48\ub10.03\ub10.03\ub10.05, where the last uncertainty is due to those on the branching fractions of the J/\u3c8\u2192pp\uaf and \u3b7c\u2192pp\uaf decays. The difference between the J/ \u3c8 and \u3b7c(1 S) masses is also determined to be 113.0\ub10.7\ub10.1MeV, which is the most precise single measurement of this quantity to date