Detection limits for natural circular dichroism of chiral complexes in the x-ray range

Abstract

Whereas both Magnetic Circular Dichroism and Faraday Rotation studies have been successfully carried out at the K-, L- and M- absorption edges of metal atoms in ferromagnetic systems, Natural optical activity of chiral complexes has not yet been detected quite unambiguously in the X-ray range. We review a number of theoretical arguments which confirm that the optical asymmetry factor gG should be very small in the X-ray range for unoriented powdered samples, especially at the K-absorption edges. This stimulating challenge prompted us to start an intensive programme of measurements aimed at detecting natural circular dichroism in both the soft and “firm” X-ray ranges. Although some of our experiments look consistent with the presence of the expected effect, our conclusions cannot be taken yet as definitive due to the presence of a weak residual signal which, unfortunately, could not be eliminated. © 1993 The Japan Society of Applied Physics.