Knowledge Bank

Quantitative infrared absorption spectra of liquid $C6H5D$ at $25\circ C$ have been measured between 6250 and $400cm-1$ through transmission cells fitted with NaCl and KBr windows. The spectra have been fully corrected for reflection effects and the real, n, and imaginary, k, refractive indices of the liquid have been calculated thoughout this range. To correct for the predictable long-range dielectric effects in the liquid, the Lorentz local field was used to calculate the complex molar polarizability. As has been described previously for liquid $methanola$ and liquid $C6D6b$, the contributions of the different bands to the imaginary molar polarizability spectrum were separated by fitting the spectrum with Classical Damped Harmonic Oscillator bands, and the absolute integrated intensities were calculated analytically from the parameters of the CDHO bands. The methods used will be illustrated sufficiently to give confidence in the claimed 5 to 10 percent accuracy of the integrated intensities of liquid $C6H5D$, which will be related to those of the gas and to those of $C6H6$ and $C6D6$. In passing, a noteworthy, but not surprising, similarity will be shown between the first CH overtone spectrum of liquid $C6H6$ at $25\circ Cc$ and that of $C6H6$ in a supersonic beam at a rotational temperature temperature of $5Kd$.