In the first table in attached link are listed pheophytins corresponding to chlorophylls. However, Wikipedia speaks about pheophytin as about single compound. So I want to check, whether is it really group of compounds.
In such case, which pheophytins are in respective photosystems?
http://www.bio.ku.dk/nuf/resources/scitab/chlabs/index.htm
I am not a pigment chemist, but my impression is that phaeophytins are chorophylls with the magnesium removed, as happens under acidic conditions - so for each chlorophyll there will presumably be a corresponding phaeophytin.
"Pheophytins" is the common name for a group of compounds, as same as "chlorophylls", and that's why you could find Pheophytin a, etc... that are analogous to Chlorophyll a, etc... but without the central Mg+2 (also for Bacteriochlorophylls and Bacteriopheophytins). Biologically, in higher plants and algae, we can find only pheophytin a, as part of de photosynthetic thylakoid proteins. For further reading, I recommend you the book: Grimm, Porra, Rüdiger and Scheer (2006) Chlorophylls and Bacteriochlorophylls: Biochemistry, Biophysics, Functions and Applications; Advances in Photosynthesis and Respiration (Govindjee, Series Editor), Vol. 25.
For each single chlorophyll (e.g., Chl a, Chl a, Bchl a, ...), there is a single pheophytin, in which the Mg atom in the center is replaced by 2 H atoms covalently attached to two of the pyrrole rings. So, pheophytins may be taken as a class, but if you're talking about a specific chlorophyll molecule, there is only one corresponding pheophytin.
Wikipedia contains valuable information but without references one cannot consider as a 100 % evidence in science. There are plenty of scientific book and publications dealing with these pigments. In general, if the Mg leaves the porphyrin ring, the resulted compound belongs to the pheophytin family. Consequently, chlorophyll-a is the source of pheophytine-a, chlorophyll-b is the source of pheophytin-b, etc. One can identify pheophorbide-a or pheophorbide-b the source of which is chlorophyllide-a and chlorophyllide-b, respectively, or protopheophytin and ptotopheophobide produced from protochlorophyll or protochlorophyllide, respectively. Similar products can be produced from teh bacteriochlorophylls.
A small detail: when the absorption spectra are discussed, the solvent is very important, as you can see in the referred homepage. However, for spectroscopic identification pure solvent should be used in which these pigments form monosolvate complexes (one pigment+one solvent molecule); this ensures the well-defined extinction coefficients and absorption maxima.
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