The Spectral Line Narrowing Problem and a Computer Program Based on the Gulf Tuning Method

Abstract

Discovering the exact positions and heights of spectral lines is a familiar problem to those dealing with line spectra. This information is often obscured by overlap of the individual lines, since spectral lines are always broadened due to, for example, random interactions of radiating particles or the imperfections of the measuring device. Unravelling overlapping lines is, however, a very ill-behaved problem, extremely sensitive to noise. Owing to the very high signal-to-noise ratios attainable by modern spectrometers, this kind of resolution enhancement has now become possible in principle. There nevertheless seems to be a lack of suitable line narrowing algorithms and programs for accomplishing this procedure. In this paper the problem of spectral line narrowing is approached first from a purely theoretical viewpoint. The factors distorting the output of a line narrowing procedure are considered one at a time. After that, a novel line narrowing algorithm, the gulf tuning method, which has been programmed and tested with simulated spectra and real FT-IR spectra, is described.