Population of a low-spin positive-parity band from high-spin intruder states in 177Au : The two-state mixing effect

The extremely neutron-deficient isotopes 177,179Au were studied by means of in-beam γ-ray spectroscopy. Specific tagging techniques, α-decay tagging in 177Au and isomer tagging in 179Au, were used for these studies. Feeding of positive-parity, nearly spherical states, which are associated with 2d3/2 and 3s1/2 proton-hole configurations, from the 1i13/2 proton-intruder configuration was observed in 177Au. Such a decay path has no precedent in odd-Au isotopes and it is explained by the effect of mixing of wave functions of the initial state

Depth profile study of polyaniline films by photoacoustic spectroscopy

In this study, we carried out a depth profile analysis of the optical properties of undoped and doped polyaniline (PANI) films, using photoacoustic spectroscopy (PAS). As the thermal diffusion length varies inversely to chopper modulation frequency, then at high chopping frequencies information about the sample near the surface is obtained, while at low chopping frequencies the data come from deeper within the sample. The objective of this study is to analyze how the polyaniline doping process in acidic media occurs in the polymeric chain. The results showed that the undoped sample is, in reality, slightly doped and the polymeric chain of the doped samples is formed by undoped regions. On the other side, the polymeric chain of the undoped samples presents doped regions in lower degree. These conclusions are in concordance with published results which is the granular metal model of doped PANI. This model explains the polyaniline polymeric chain as it is formed by conducting islands on a sea of insulating material. Also, our experimental results showed that the doping process of PANI films, that is, immersing the films in HCl solution, occurs better in the external surface of the films

Analysis Of Polyaniline Films Using Atomic Force Microscopy

This work presents a morphological study of polyaniline (PANI) films, chemically and electrochemically synthesised over ITO (Indium Tin Oxide covered glass) substratum using atomic force microscopy (AFM). From AFM images we calculate the fractal dimension of the polyaniline formed films using power spectral density (PSD) and the box counting method (roughness versus scale). As a result it is shown that the fractality obtained by PSD are in good agreement with box counting.374191200Gonzalez, R.G., Wintz, P., (1987) Digital Image Processus, , Addison-Wesley, ReadingVatel, O., Dumas, P., Chollet, F., Salvan, F., André, E., Roughness assessment of polysilicon using power spectral density (1993) Jpn. J. Appl. Phys., 32, p. 5671Mitchell, M.W., Bonnel, D.A., Quantitative topographic analysis of fractal surfaces by scanning tunneling microscopy (1990) J. Mater. Res., 5 (10), p. 2244Mandelbrot, B.B., (1983) The Fractal Geometry of Nature, , W. H. Freeman and Company, New YorkMandelbrot, B.B., (1977) Fractals Form, Chance, and Dimension, , W. H. Freeman and Company, San FranciscoMandelbrot, B.B., Passoja, D.E., Paullay, A.J., Fractal character of fracture surfaces of metals (1984) Letters to Nature, 308, p. 721Vatel, O., Dumas, P., Chollet, F., Salvan, F., Andre, E., Roughness assessment of polysilicon using power spectral density (1993) Jpn. J. Appl. Phys., 32, p. 5671Barabási, A.L., Stanley, H.E., (1995) Fractal Concepts in Surface Growth, , Cambridge, Cambridge University PressRuss, J.C., (1994) Fractal Surfaces, , Plenum Press, New York and LondonKiely, J.D., Bonneli, D.A., Quantification of topographic structure by scanning probe microscopy (1997) J. Vac. Sci. Technol. B, 15 (4), p. 148

Langmuir films of an oligo(p-phenylene vinylene) functionalized with a diaminotriazine head group

A detailed investigation is presented on the Langmuir film characteristics of a novel substituted oligo(p-phenylene vinylene) with a diaminotriazine headgroup, namely, 6-[4-{4-(3,4,5-tridodecyloxystyryl)-2,5-bis[(S)-2-methylbutoxy]styryl}-2,5-bis[(S)-2-methylbutoxy]styryl]phenyl-2,4-diamino-1,3,5-triazine (OPVT). The films were characterized by recording surface pressure (p-A) and surface potential (¿V-A) isotherms, in addition to Brewster angle microscopy (BAM). The limiting mean molecular area indicates formation of a monomolecular Langmuir film of OPVT at the air-water interface. The dependence of a plateau transition in the p-A isotherm on experimental conditions is studied. The critical area for the increase in surface potential revealed the interaction of OPVT molecules even at a large area per molecule, supported by BAM images. On the basis of the data, we propose a model for the organization of OPVT molecules at different stages of film compressio

Donor-acceptor Copolymers With Internal Dipole Change For Organic Photovoltaic Applications

We present the synthesis and the characterization of a series of conjugated D-A copolymers, where the molecular structure, in which the changes of dipole moments by photoexcitation facilitate the electronic transitions. The dynamics of the PL process for the PFeBT suggests a model where two types of acceptor groups might be present, which would be responsible by the biexponential decays. These two decays are not related to interlumophoreinteractions but with lumophores in relaxed and unrelaxed forms. The dynamics of the PL process for the others polymers as underway, as well as the photovoltaic characterization. © 2012 OSA.Inganas, O., Zhang, F., Tvingstedt, K., Andersson, L.M., Hellstrom, S., Andersson, M.R., (2010) Adv. Mater, 22, pp. E100-E11