Wedge shaped cell for highly absorbent liquids: infrared optical constants of water

We designed an improved wedge shaped cell for measuring Lambert absorption coefficient spectra alpha(nu) of highly absorbent liquids. The design allows for accurate determination of the apex angle of the wedge, sealing the cell, and injection of the liquid without disassembling the cell. We measured alpha(nu) for water through the 500-12,500-cm(-1) wavenumber region to determine the range of alpha(nu) for which the cell provided accurate measurements. We then determined the imaginary part of the complex refractive index N(nu) = n(nu) + ik(nu) from alpha(nu) and used Kramers-Kronig methods to compute n(nu) from k(nu).