Dataset Information

Long-Time Relaxation of Stress-Induced Birefringence of Microcrystalline Alkali Halide Crystals.

ABSTRACT: Alkali halide single crystals are most commonly used as the diluent matrix in the tablet method or disk technique for spectroscopic measurements. However, stress-induced birefringence (SIB) of alkali halides as well as intrinsic birefringence manifest during the disk formation process. Thus, the true chiroptical measurement is disturbed by optical anisotropies (OA) containing SIB and intrinsic birefringence, except in the case of optical homogeneity. SIB is generally larger than intrinsic birefringence and has a value of several thousand millidegrees in the ultraviolet-visible wavelength range, although this varies with disk type. Here, to investigate the SIB origin, alkali halide crystals were examined using polarized light, X-ray diffraction, Fourier-transform infrared, and electron backscattering diffraction spectroscopic measurements. It was found that, after stress release, the SIB exhibited nonlinear long-time relaxation, which roughly converged within several hours, with the only time-invariant intrinsic birefringence remaining being due to OA. This behavior was strongly related to an increase in the quasi-amorphous domain and the generation of an air gap between the crystallite boundaries and their pellets. Further, a straightforward correlation was found between amorphization and an increase in the disk water content caused by deliquescence. Thus, the OA of alkali halide single crystals was found to have two different origins yielding intrinsic birefringence and SIB.

SUBMITTER: Ueno H

PROVIDER: S-EPMC6017667 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Publications

Long-Time Relaxation of Stress-Induced Birefringence of Microcrystalline Alkali Halide Crystals.

Ueno Hiroki H Arakane Ryoga R Matsumoto Yoshihisa Y Tsumura Tomoki T Kitazaki Akihito A Takahashi Toru T Hirao Shotaro S Ohga Yasushi Y Harada Takunori T

Molecules (Basel, Switzerland) 20180325 4

Alkali halide single crystals are most commonly used as the diluent matrix in the tablet method or disk technique for spectroscopic measurements. However, stress-induced birefringence (SIB) of alkali halides as well as intrinsic birefringence manifest during the disk formation process. Thus, the true chiroptical measurement is disturbed by optical anisotropies (OA) containing SIB and intrinsic birefringence, except in the case of optical homogeneity. SIB is generally larger than intrinsic birefr ...[more]

PMID: 29587395

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Dataset Information

Long-Time Relaxation of Stress-Induced Birefringence of Microcrystalline Alkali Halide Crystals.

Publications

Long-Time Relaxation of Stress-Induced Birefringence of Microcrystalline Alkali Halide Crystals.

Similar Datasets

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