A New, Simple Approximation for the Deconvolution of Instrumental Broadening in Spectroscopic Band Profiles

A robust empirical correction formula has been developed for the approximation of Lorentzian widths, using a known spectrometer bandpass, in instrument-broadened Voigt bands in optical spectra. The relationship between analytically calculated [(W-Voigt - W-Lorentz)/ W-Gauss] and [W-Voigt/W-Gauss - 1] values (where w is the full width at half-maximum [FWHM]) is analyzed to derive the formula for the approximation of the (W-Voigt - W-Lorentz) difference. The precision of the method is demonstrated by comparing its performance to several previously published numerical correction approaches. The fraction of the Lorentzian contribution in Voigt FWHMs is evaluated in terms of the Gaussian FWHM to assess the conditions under which the deconvolution of instrumental broadening is necessary.