A one-sided Loomis-Wood plot

Another promising area for pattern recognition is when the pattern sought consists of many elements and the spectrum in which the pattern is to be located is very complex and congested, possibly because the spectrum consists of several spectrally shifted copies of the same many-line pattern. Neuhauser, et al., (1998) have proposed the CRIES (Cross-Correlation Ionization Energy Spectroscopy) scheme for picking out many overlapped Rydberg series, each described by 

It is possible to record a dispersed fluorescence spectrum where the only lines present are a vibrational progression of R, P doublets that correspond to a single set of lower electronic state rotational combination differences, 

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