Measurement of Vibrational Circular Dichroism below ∼600 cm −1 : Progress towards Meeting the Challenge

The measurement of vibrational circular dichroism (VCD) below ∼600 cm⁻¹ is one of the experimental challenges of the current times. Polarization-division interferometry is considered to be the most efficient approach for realizing these measurements. A crucial component for successful applications of this interferometry is the beamsplitter, which divides the incoming beam according to polarization. Free-standing metal wires and the metal wires deposited on a mylar substrate have been employed as beamsplitters, and their performance has been evaluated for the ∼700–10 cm⁻¹ region. VCD measurements obtained for the enantiomers of α-pinene in the 400–250 cm⁻¹ region are presented. The current status and future developments needed for routine far-infrared VCD measurements are summarized.