Revisiting polarimetry near the isotropic point of an optically active, non‐enantiomorphous, molecular crystal

Abstract

Accurate polarimetric measurements of the optical activity of crystals along low symmetry directions are facilitated by isotropic points, frequencies where dispersion curves of eigenrays cross and the linear birefringence disappears. We report here the optical properties and structure of achiral, uniaxial (point group D ) potassium trihydrogen di-(cis-4-cyclohexene-1,2-dicarboxylate) dihydrate, whose isotropic point was previously detected (S. A. Kim, C. Grieswatch, H. Küppers, Zeit. Krist. 1993; 208:219-222) and exploited for a singular measurement of optical activity normal to the optic axis. The crystal structure associated with the aforementioned study was never published. We report it here, confirming the space group assignment I 4¯c2, along with the frequency dependence of the fundamental optical properties and the constitutive tensors by fitting optical dispersion relations to measured Mueller matrix spectra. k-Space maps of circular birefringence and of the Mueller matrix near the isotropic wavelength are measured and simulated. The signs of optical rotation are correlated with the absolute crystallographic directions.

Optical rotation in the lithium triborate nonlinear crystal

“…One should note that it is not easy to determine the sign of the ORP in a linearly birefringent crystal section, but sometimes this task is simplified if the linear birefringence passes through zero for a specific light wavelength (Hobden, 1967(Hobden, , 1969Lingard & Renshaw, 1994;Martin et al, 2018). In the case of the LBO crystal, we have experimentally determined The characteristic differences Á 0 01 and Á 90 01 and their dependencies on cotðÀ=2Þ for = 633 nm (blue) and 661 nm (red) laser wavelengths obtained for 0 and 90 crystal sets in the PSA system.…”

“…In particular, the first observations of optical activity in AgGaS 2 (Hobden, 1967) and CdGa 2 S 4 (Hobden, 1969) crystals are well known; these crystals are optically isotropic for one wavelength and the rotation of the plane of polarization has been measured. But from the time of the overview by Claborn et al (2008) of the optical rotation of nonenantiomorphous crystals, little has changed in terms of their research (Arteaga, 2015;Martin et al, 2018Martin et al, , 2021 because such experiments are, usually, quite complicated and the acquired data need very careful and thorough processing.…”

Mueller matrix polarimetry of bianisotropic materials [Invited]

“…Those measured before the year 2000 were tabulated by Kaminsky [70] and those between 2000 and today by Martin [71]. The majority of these crystals were analyzed by HAUP but Mueller matrix polarimetry was recently used to analyze ethylene diammonium sulfate [72] and the isomorphous selenate [73]. These crystals, while isostructural, are distinct in that the selenate has an isotropic point at 364 nm (3.41 eV), where the ordinary and extraordinary refractive indices coincide.…”

“…As a case study, we will review ethylene diammonium selenate [73]. Like its isomorphous sulfate, it is a lamellar crystal with a nearly perfect cleavage perpendicular to the optic axis.…”

Computed Gyration Tensors of Knotted Chiral and Achiral Topological Stereoisomers of C60 Cyclocarbons

“…[27,28] Older papers [29] that recent researchers [12] have cited use a definition for signs of crossings which is the opposite of topologists and the majority of chemists today. [24] Even though an S 4 structure has an improper rotation axis and is achiral, oriented structures or crystals of such a symmetry are indeed optically active in some directions [30] and we have made calculations [31][32][33] and measurements [34,35] of the orientational dependencies of OA of a variety of non-enantiomorphous structures. Most relevant here is an analysis of the OA of cyclo [18]carbon hydrogenation products, C 18 H 2n , where n = 1-8.…”