TY  - JOUR
A1  - Breu, J.
A1  - Stossel, P.
A1  - Schrader, Sigurd
A1  - Starukhin, A.
A1  - Finkenzeller, W. J.
A1  - Yersin, H.
T1  - Crystal structure of fac-Ir(ppy)(3) and emission properties under ambient conditions and at high pressure
N2  - Solution and refinement of the crystal structure of fac-Ir(ppy)(3) is severely hampered by systematic twinning and pseudo-symmetry.fac-Ir(ppy)(3) Crystallizes in the centrosymmetric space group P (3) over bar as has been deduced from single-crystal structure refinement and investigations of the second harmonic generation (SHG) of fac-Ir(ppy)(3) powder as compared to two standard materials. The topology of the molecular packing of fac-Ir(ppy)(3) is identical to the packing observed for [Ru(bpy)(3)](0), however, the site symmetry of all Ir(ppy)(3) molecules is necessarily lowered from D-3 to C-3. Packing motifs with intermolecular "pi-pi interactions" of T-shaped and "shifted pi stack" geometry are realized. The systematic twinning leads to the occurrence of crystalline domains with rigorously alternating chirality within the bulk of the domains but with homochiral fac-Ir(ppy)(3) contacts at the domain interfaces. These differences in packing motifs are displayed in the emission spectra and in the high-pressure-induced shifts of the emission. The emission maximum of the bulk material at 18 350 cm(-1) (545 nm) and of the domain interfaces at 19 700 cm-1 (507 nm) experience for p < 25 kbar and T = 295 K red shifts of Delta nu/Delta p = -(12 +/- 2) cm(-1)/kbar, and -(22 +/- 4) cm(- 1)/kbar, respectively
Y1  - 2005
SN  - 0897-4756
ER  - 
TY  - JOUR
A1  - Fazio, V. S. U.
A1  - Lagerwall, S. T.
A1  - Zauls, V.
A1  - Schrader, Sigurd
A1  - Busson, P.
A1  - Hult, A.
A1  - Motschmann, H.
T1  - Nonlinear optical properties of a channel waveguide produced with crosslinkable ferroelectric liquid crystals
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Flueraru, C.
A1  - Schrader, Sigurd
A1  - Zauls, V.
A1  - Motschmann, H.
T1  - Sensitivity analysis of ellipsometry applied to uniaxial optical films
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Holzer, Wolfgang
A1  - Penzkofer, Alfons
A1  - Schrader, Sigurd
A1  - Grimm, Bernhard
T1  - Photo-physical and lasing characterisation of a polyparaphenylenevinylene (PPV) neat film
N2  - The wave-guided travelling-wave laser action (amplified spontaneous emission) of a neat film of poly(p- phenylenevinylene) (PPV) on a quartz glass substrate prepared by a sulfinyl precursor technique is studied. The samples are transversally pumped with picosecond excitation pulses (wavelength 347.15 nm, duration 35 ps). Lasing occurs at 550 nm. The optical constants of the neat films are determined by transmittance measurements exploiting the multiple beam interference in the transparency region. A fluorescence spectroscopic characterisation is carried out determining the fluorescence quantum distribution, fluorescence quantum yield, degree of fluorescence polarisation, and fluorescence lifetime. The emitting chromophore size (emitting singlet exciton extension) is determined by the ratio of exciton radiative lifetime to repeat-unit based radiative lifetime. The obtained size of about two repeat units is discussed in a disordered solid-state polymer model
Y1  - 2005
SN  - 0306-8919
ER  - 
TY  - JOUR
A1  - Möller, Gunter Eric
A1  - Schrader, Sigurd
A1  - Motschmann, H.
A1  - Prescher, Dietrich
T1  - Influence of a base electrolyte on the adsorption behavior of an anionic surfactant as observed by second harmonic generation
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Nagy, A.
A1  - Strahl, A.
A1  - Neuhauser, H.
A1  - Schrader, Sigurd
A1  - Behrens, I.
A1  - Peiner, E.
A1  - Schlachetzki, A.
T1  - Mechanical spectroscopy of thin layers of PPV polymer on Si substrates
N2  - The vibrating reed technique with electro "static" excitation and optical detection has been applied to investigate thin layers of poly-phenylene-vinylene, deposited by spin coating onto microfabricated Si cantilevers, during temperature cycling programs between 90 and 540 K at a rate of 1 K/min. From the vibration frequencies the Young's modulus of the film can be estimated to be about 10 MPa at room temperature in the precursor phase (if prepared from a solution in toluene), which increases by conversion to the conjugate bonded polymer to about 50 MPa. The temperature dependence of internal friction reveals the processes of gamma relaxations (crankshaft motion of side branches in the precursor) and P-relaxation (movements of a few monomer blocks in the polymer chain), as well as peaks indicating the structural transformations during conversion, and possibly a glass transition in the amorphous precursor phase. After conversion only the P-relaxation persists. (C) 2003 Elsevier B.V. All rights reserved
Y1  - 2004
SN  - 0921-5093
ER  - 
TY  - JOUR
A1  - Otto, Andreas H.
A1  - Prescher, Dietrich
A1  - Gey, E.
A1  - Schrader, Sigurd
T1  - Proton affinities of some polyfluoroalkanes in comparison to the unsubstituted alkanes. The estimation of the proton affinities of polyfluorethylene and polyethylene by applying theoretical methods
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Otto, Andreas H.
A1  - Schrader, Sigurd
A1  - Steiger, Th.
A1  - Schneider, M.
T1  - Gas phase deprotonation energies of Sulfuric Acid, Perchloric Acid, Chlorsulfuric Acid and Fluorosulfuric Acid
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Otto, Andreas H.
A1  - Steiger, Th.
A1  - Schrader, Sigurd
T1  - The gas phase acidity of trifluoromethanesulphonic acid : an ab initio MO and density functional theory study
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Otto, Andreas H.
A1  - Steiger, Th.
A1  - Schrader, Sigurd
T1  - HAICI4 in the gas phase is stronger than HTaF6.
Y1  - 1998
ER  -