摘要:

The real path of the polarized radiation in passing throughout an anisotropic crystal essentially depends on the orientation of the principal dielectric tensor axes with respect to the cleavage plane of the sample. Proper elucidation of this fact leads to new expressions for the dichroie ratio of a molecular crystal which contains terms connected both with the orientation of molecular transition moments and with the dielectric tensor axes as well. The agreement of the theory with experiment is illustrated in several examples.

ISSN:0369-1152    

DOI:10.1080/15421406808082936

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

EPR Studies of radiation damage in anthracene C14H10and deuterated anthracene (C14D10) powders have been made up to a dose of 7 × 108rad. Interpretation of the spectra is consistent with that resulting from the hyperfine interaction of three equivalent protons. Excessive breadth of the spectrum of the radical produced in C14D10is attributed to a high concentration of incompletely deuterated radical resulting from the presence of C14D9H.

ISSN:0369-1152    

DOI:10.1080/15421406808082937

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Second Harmonic Generation of light (SHG) is used as a probe to study the structure of the nematic, cholesteric or smectic mesophases of various liquid crystals, with non centro-symmetric molecules. In one case (cholesteryl 2-(2-ethoxy ethoxy) ethyl carbonate) where SHG has already been reported, it is shown that SHG occurs in the crystalline rather than the mesomorphic phase. In all cases, no evidence is found of any SHG in any mesophase. Consequently, these are probably centrosymmetric by compensation, as is the normal liquid phase.

ISSN:0369-1152    

DOI:10.1080/15421406808082938

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The problem of the damping of molecular exciton states in a crystal is considered with respect to the trapping of the exciton at a particular site, and the subsequent radiationless transition within a molecule at the site. Damping considered in this manner has a close connection with the proposals concerning radiationless transitions put forward by Robinson and Frosch. In this paper we make use of the Robinson and Frosch proposals together with the harmonic oscillator representation of the exciton problem to show that damping at a particular site leads to damping of the exciton.

ISSN:0369-1152    

DOI:10.1080/15421406808082939

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

In a recent series of papers, Ashidaet al.1investigated the crystal structures of several metal phthalocyanine thin films. Ashida obtained two types of films which he assumed had identical crystal structures but in different orientations. A comparison of Ashida's data with other published data (Honigman2) suggest that the structures in the two types of thin films may be different and have different space groups.

ISSN:0369-1152    

DOI:10.1080/15421406808082940

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor