A photoelectric absorption with variable abundances using
Balucinska-Church and McCammon (ApJ 400, 699) cross-sections. The
column
for each
element is in units of the column in a solar abundance column of an
equivalent hydrogen column density of 
cm
. The Solar
abundance table used is set by the abund command.
par1-par18 = equivalent columns for H, He, C, N, O, Ne, Na, Mg, Al,Si, S, Cl, Ar, Ca, Cr, Fe, Co, Ni