Surface dependent behaviour of CdS LO-phonon mode

Abstract

We have carried out continuum and line polarization observations of two protoplanetary nebulae (PPNe), CRL 618 and OH 231.8+4.2, using the Submillimeter Array in its compact configuration. The frequency range of observations, 330-345 GHz, includes the CO(J=3?2) line emission. CRL 618 and OH 231.8+4.2 show quadrupolar and bipolar optical lobes, respectively, surrounded by a dusty envelope reminiscent of their asymptotic giant branch phase. We report a detection of dust continuum polarized emission in both PPNe above 4s but no molecular line polarization detection above a 3? limit. OH 231.8+4.2 is slightly more polarized on average than CRL 618 with a mean fractional polarization of 4.3 and 0.3 per cent, respectively. This agrees with the previous finding that silicate dust shows higher polarization than carbonaceous dust. In both objects, an anticorrelation between the fractional polarization and the intensity is observed. Neither PPNe shows a well-defined toroidal equatorial field, rather the field is generally well aligned and organized along the polar direction. This is clearly seen in CRL 618 while in the case of OH 231.8+4.2, the geometry indicates an X-shaped structure coinciding overall with a dipole/polar configuration. However in the later case, the presence of a fragmented and weak toroidal field should not be discarded. Finally, in both PPNe, we observed that the well-organized magnetic field is parallel with the major axis of the 12CO outflow. This alignment could indicate the presence of a magnetic outflow launching mechanism. Based on our new high-resolution data we propose two scenarios to explain the evolution of the magnetic field in evolved stars. " 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.",,,,,,"10.1093/mnras/stt2318",,,"http://hdl.handle.net/20.500.12104/44833","http://www.scopus.com/inward/record.url?eid=2-s2.0-84893355398&partnerID=40&md5=8d50dcbbb2445b7809593556cb369e38",,,,,,"2",,"Monthly Notices of the Royal Astronomical Society",,"1794

1804",,"438",,"Scopus

WOS",,,,,,"AGB and post-AGB-stars individual; CRL 618-stars individual; magnetic fields-polarization-stars; OH 231.8+4.2.",,,,,,"Submillimetre polarization and magnetic field properties in the envelopes of protoplanetary nebulae CRL 618 and OH 231.8+4.2",,"Article" "46665","123456789/35008","Katime, I., Grupo de Nuevos Materiales, Departamento de Química Física, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain; Velada, J.L., Grupo de Nuevos Materiales, Departamento de Química Física, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain; Novoa, R., Grupo de Nuevos Materiales, Departamento de Química Física, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain; Díaz De Apodaca, E., Grupo de Nuevos Materiales, Departamento de Química Física, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain; Puig, J., Departamento de Química, Universidad de Guadalajara, Jalisco, Mexico; Mendizabal, E., Departamento de Química, Universidad de Guadalajara, Jalisco, Mexico

Mendizábal, E. M., Universidad de Guadalajara. Centro Universitario de Ciencias Exactas e Ingenierías",,"Katime, I.

Velada, J.L.

Novoa, R.

Diaz De Apodaca, E.

Puig, J.

Mendizábal, E. M.",,"1996",,"Hydrogels of mono-n-alkyl itaconate/N-acrylamide have been synthesised. The swelling process at three different pH values (acid, neutral and basic) has been studied. The experimental data indicate that our hydrogels follow second-order swelling kinetics. According to this, the kinetic constant, K?, and the swelling capacity at equilibrium, W?, have been calculated. The influence of the solvent pH and the molar mass of the mono-n-alkyl itaconate monomeric unit has been analysed. It seems that the general balance between the hydrogen bonding and the hydrophobic interactions regulates the swelling process of these hydrogels. © 1996 SCI.",,,,,,,,,,"http://www.scopus.com/inward/record.url?eid=2-s2.0-0030212964&partnerID=40&md5=ed341e628db7a4aa48975334e55d8713

http://hdl.handle.net/20.500.12104/44886",,,,,,"4",,"Polymer International",,"281

286",,"40",,"Scopus

WOS",,,,,,"Hydrogel; Mono-n-alkyl itaconate; N-acrylamide; Swelling kinetics; Xerogel",,,,"Swelling kinetics of poly(acrylamide)/poly(mono-n-alkyl itaconates) hydrogels",,,,"Article", "46636","123456789/35008",,"Molina-Contreras, J.R., Departamento de Ingeniería Eléctrica y Electrónica, Instituto Tecnológico de Aguascalientes, Av. López Mateos 1081 Oriente, CP 20256. Aguascalientes, Ags., Mexico; Medina-Gutiérrez, C., Universidad de Guadalajara, Centro Universitario de Los Lagos, Av. Enrique Diaz de Leon s/n, CP 47460, Lagos de Moreno, Jal., Mexico; Frausto-Reyes, C., Centro de Investigaciones en óptica AC, Unidad Aguascalientes, Prolong., Constitución 607, Apartado Postal 507, CP 20200, Ags., Mexico; Trejo-Vázquez, R., Departamento de Ingeniería Eléctrica y Electrónica, Instituto Tecnológico de Aguascalientes, Av. López Mateos 1081 Oriente, CP 20256. Aguascalientes, Ags., Mexico; Villalobos-P?a, F.J., Departamento de Ingeniería Eléctrica y Electrónica, Instituto Tecnológico de Aguascalientes, Av. López Mateos 1081 Oriente, CP 20256. Aguascalientes, Ags., Mexico; Romo-Luevano, G., Intel Tecnología de México, SA de CV, Edificio 4-E, 45600 Tlaquepaque, Jalisco, Mexico; Calixto, S., Centro de Investigaciones en óptica, AC, Loma del Bosque 115, CP 37150 León, Guanajuato, Mexico",,"Molina-Contreras, J.R.

Medina-Gutierrez, C.

Frausto-Reyes, C.

Trejo-Vazquez, R.

Villalobos-Pia, F.J.

Romo-Luevano, G.

Calixto, S.",,"2007",,"In this paper, we develop a sensitive optical method to monitor the surface roughness in the investigation of surfaces. By applying this method to measure the RMS surface roughness of various surfaces, we found RMS values which are comparable to those obtained by atomic force microscopy measurements. In addition, we present a simple empirical model to calculate the RMS surface roughness which shows very good agreement with the surface roughness measurements taken by the method reported in this paper. Finally, the application of our method to the study of the LO-phonon mode of CdS suggests that its intensity is dominated by the surface roughness. This roughness dependent behaviour of the CdS LO-phonon mode is experimentally confirmed by using an excitation wavelength near its E0 transition. " 2007 IOP Publishing Ltd.