摘要:

Physical properties derived from proton-dynamics in hydrogenbonded molecular crystals are discussed from two aspects. First, the effect of a static or dynamic modulation is discussed on conduction property of Ni(dmit)2caused by a hydrogen-bonded counter cation system. An anomaly was observed in conduction property of Ni(dmit)2· Lin(H2O)msalt which is presumably due to a change in the hydration scheme. Second, physical properties of hydrogen-bonded tautomeric molecules are examined in the case of 3-hydroxy-phenalenone (1) and its derivative (2). No dynamic processes were detected in the crystals of1, although the crystal is polar and exhibits second harmonic generation. On the other hand the crystal of 2carboxy derivative 2 behaves as paraelectrics at room temperature at ambient pressure with a phase transition to an antiferroelectric phase at 40 K. This remarkable property is ascribed to the rapid tautomerization mediated by 2-carboxyl substituent coupling with proton-transfer in intermolecular bifurcated hydrogen bonds.

ISSN:1058-725X    

DOI:10.1080/10587259208047056

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Absorption spectra and TEM and STM images are observed on C60thin films prepared by MBE technique. Superconductivity behaviors of alkali metal-doped single crystals and thin films are also reported.

ISSN:1058-725X    

DOI:10.1080/10587259208047057

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We have used the combined microwave spectroscopy: the nonresonant microwave absorption in low-magnetic field (so-called LFS) together with conventional ESR for the search and study of superconductivity (SC) in the new family of fullerene molecular solids: C60, C70, C76, C78, C84C90, and their alloys ((C60)1-y(C70)y), doped by different metals (K, Rb, In, and Ga) and iodine I2. These experiments fall into two categories: 1) Search for SC in higher fullerenes and study of the evolution of SC properties upon doping of pure (one component) fullerenes including Cm thin films. 2) Investigation of the Tcchange in molecular alloys of Mx(C60)1-y(C70)ytype. In the first category of experiments we discuss the evolution of LFS and ESR spectra upon variation of Rb-doping conditions: temperatures of doping: Td(C60), Td(M), and doping time td, and as a result we find the optimal conditions for vapour phase Rb-doping. Here we demonstrate that SC Tcappears and disappears with doping abruptly at a discrete value Tc28K for RbxC60similar to case of KxC60with a discrete Tc= 19K. It is shown that MxCn(n=70,76,78,84,90), InxC60, and GaxC60do not show SC phase at least at T>5K, while ESR changes dramatically upon doping. IxC60doped in ESR tubes at Td(C60,I2)=210° and 260°C also do not show LFS meaning absence of SC transition. However intensive ESR-signal appears proving the Occurrence of p-type charge transfer doping. In the second category we have found that Tcis strongly suppresed with increase ofyin molecular alloys of Kx(C60)1-y(C70)y, and in Rbx(C60)1-y(C70)y.

ISSN:1058-725X    

DOI:10.1080/10587259208047058

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:1058-725X    

DOI:10.1080/10587259208047005

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor