Faraday Rotation Dispersion Measurements of Diamagnetic Organic Liquids and Simultaneous Determination of Natural Optical Rotatory Dispersion Using a Pulsed Magnetic Field

Abstract

We constructed an apparatus to measure the wavelength dispersion of the Faraday rotation in the visible region, and determined the Verdet constants of diamagnetic organic liquids, including aliphatic compounds, benzene derivatives, and naphthalene derivatives. These three groups were easily distinguished by the magnitudes of their Verdet constants. Based on the theory developed by Serber, we determined the enhancing effect of π*←π transitions on the visible-light Faraday rotation angles observed for aromatic compounds. Furthermore, we propose a novel approach for simultaneously observing Faraday rotation dispersion and natural optical rotatory dispersion.

Faraday Rotation Dispersion Microscopy Imaging of Diamagnetic and Chiral Liquids with Pulsed Magnetic Field

“…The Verdet constants of several liquids were also measured and summarized in Table . All observed values were in good agreement with those measured in the previous study . Therefore, it was concluded that quantitative FR images could be obtained using a rotation angle and Verdet constant measured by the present microscopic FR system.…”

“…Figure (a) is the plots of the average FR angle against the wavelength. The solid lines indicate the calculated value from the Verdet constants measured in the previous study, taking into account the present experimental condition ( l = 200 μm and B = 1.2 T). For every sample, the results were in good agreement with those measured with the nonmicroscopic apparatus for FR dispersion.…”

“…To confirm the wavelength dependence of the FR images, separately from the imaging experiment mentioned above, FR dispersion, so-called magneto-optical rotatory dispersion (MORD), of organic liquids was measured by the nonmicroscopic system in the wavelength region from 390 to 650 nm. The details of the setup for the dispersion measurement were described in the previous paper . A glass cylindrical cuvette with the optical path length of 7 mm was used.…”

“…In the latter case, the Faraday B -terms are larger than the other terms because these molecules have no magnetic moment, and most molecules have no degeneracy both in the ground state and in the excited states. We have observed the wavelength dispersion of the FR in organic liquids and have demonstrated that the resonance wavelength lying in the UV region can be determined from the FR dispersion curve observed in the transparent visible region . Furthermore, it has also been demonstrated that the natural optical rotatory (NOR) dispersion in chiral liquids can simultaneously be measured.…”

Giant Faraday Rotation in Mesogenic Organic Molecules

“…Unfortunately, diamagnetic organic molecules have relatively small Verdet constants in regions far from resonance. Typical Verdet constants are on the order of hundreds of degrees per tesla per meter in the visible wavelength region, displaying a continuous decline toward longer wavelengths. − Only for the larger polythiophenes in specific conditions have larger Verdet constants been reported, on the order of 10 4 deg T –1 m –1 . However, these large Verdet constants currently lack a conclusive explanation.…”