摘要:

AbstractSynthesis and investigation of the structure and electrophysical properties of two halogen hydride derivatives of isobutyl analogues of phosphatidylethanol amine (IPE), namely IPE‐HCl and IPE‐HBr, were performed to offer a new material for ‘molecular wires’ according to the model of molecular electronics developed earlier by Karasevet al.(Adv. Mater. Opt. Electron.,1994, 4, pp. 203–218). X‐ray analysis showed that isostructural crystals of the synthesised compounds are monoclinic with the space symmetry groupI2/a(C2/c). They have very similar lattice cell parameters, namelya= 21.892(8),b= 4.7747(2),c= 44.63(2) Å, β = 91.83(3)°,Z= 16 for IPE‐HCl anda= 22.115(14),b= 4.808(3),c= 44.83(2) Å, β = 91,74(5)°,Z= 16 for IPE‐HBr. It was found that the structure of IPE‐HCl contains two symmetrically unrelated molecules of IPE. They form two bilayers within the elementary cell each of which includes three zones of hydrogen bonds. The central zone is formed by NH3groups belonging to IPE and by chloride ions. The other two zones are quasi‐one‐dimensional systems of HO(SINGLE BOND)P(DOUBLE BOND)O groups generated by translationally related IPE molecules and can be considered as prospective ‘molecular wires’. These two zones are located symmetrically with respect to the central zone. Electrophysical parameters (contuctance γ and complex dielectric permittivity components ϵ′ and ϵ″) were determined for polycrystalline samples of IPE‐HCl and IPE‐HBr in the temperature range from −20 to 70°C. The permittivity ϵ′ was found to assume abnormally high values (about 106) at low frequency and to decrease monotonically with increasing temperature in the frequency range from 50 Hz to 10 MHz. Possible mechanisms of polarisation of the synthesised IPE derivatives are analysed. The conductance of the crystals was shown to have an activation character with the activation energy equal to 0.7–1.3 eV for IPE‐HCl and 0.4–0.6 eV for IPE‐HBr. A hopping mechanism was proposed to explain charge transfer along the systems of HO(SIN

ISSN:1057-9257    

DOI:10.1002/(SICI)1099-0712(199601)6:1<1::AID-AMO217>3.0.CO;2-N

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractDynamic self‐diffraction processes have been observed and analysed for methylene blue‐sensitised water‐swollen gelatine (MBSG). A degenerate two‐wave mixing experiment performed on thick samples of MBSG with 10 mW, 632.8 nm wavelength He Ne laser light allowed for the formation of phase‐ and amplitude‐transient holographic gratings. Single‐beam propagation characteristics through MBSG were measured with a Mach‐Zehnder interferometer. The observed energy transfer between the writing beams in the two‐beam coupling experiment and the considerable temporal oscillations of diffraction efficiency are explained by simple formulae. Two processes are considered: the time‐dependent phase shift between the writing beams and the transverse self‐phase modulation effects (self‐focusing and inter

ISSN:1057-9257    

DOI:10.1002/(SICI)1099-0712(199601)6:1<15::AID-AMO219>3.0.CO;2-I

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

摘要:

Abstractβ‐Co/Ga and Mn/Ga alloys have been deposited on various substrates by laser direct write chemical vapour deposition (LCVD) from novel single‐source precursors. The preformed alloy stoichiometry of 1:1 defined by the metal ratio of the precursors, (CO)4Co‐GaEt2(NMe3) (1) and (CO)5Mn‐GaEt2(NMe3) (2), is retained within the deposited structures. The depositions were up to 1.5 μm thick and the lateral dimension (4 μm) was determined by the diameter of the laser focus. The deposited structures were contaminated with ∼10 at. % C an

ISSN:1057-9257    

DOI:10.1002/(SICI)1099-0712(199601)6:1<27::AID-AMO218>3.0.CO;2-E

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe Langmuir‐Blodgett (LB) film‐forming properties of a number of novel azobenzene dye polymers are reported. The linear and second‐order non‐linear optical properties of the films have been studied using ellipsometry, visible spectroscopy and Pockels effect measurements. As monolayers, the effective electro‐opticr‐coefficients ranged from 1 to 8.7 pm V.−1When one of the polymers was combined in an alternate layer film (230 layers in total), anr13‐coefficient of 13 pm V−1was achieved. This is one of the highest values reported for

ISSN:1057-9257    

DOI:10.1002/(SICI)1099-0712(199601)6:1<33::AID-AMO222>3.0.CO;2-5

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractLinear dichroism and second‐harmonic generation (SHG) have been measured in Langmuir‐Blodgett (LB) multilayers of Z‐type structure of amphiphilic indandione‐1,3 pyridinium betaine (IPB) with an aliphatic tail containing 17 carbon atoms (C17IPB). The dichroic ratioAs/Apof electronic absorption of s‐ and p‐polarised light and the SHG intensity show that the ‘heads’ of C17IPB molecules are predominantly oriented along the deposition direction of monolayers on a quartz substrate. Orientation parameters and mean statistical azimuthal and tilt angles are evaluated as a function of the number of monolayers. The SHG efficiency has been measured in C17IPB monolayers on a water surface as a function of surface pressure. The effective hyperpolarisability β of the IPB molecule has been determined experimentally in a chloroform solution by the hyper‐Rayleigh‐scattering method. The obtained value of β = (138 ± 16) × 10−30esu is in good agreement w

ISSN:1057-9257    

DOI:10.1002/(SICI)1099-0712(199601)6:1<39::AID-AMO223>3.0.CO;2-L

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

ISSN:1057-9257    

DOI:10.1002/amo.860060107

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY

ISSN:1057-9257    

DOI:10.1002/amo.860060101

出版商:John Wiley&Sons Ltd.    

年代:1996

数据来源: WILEY