leaprc.ff86   -- Weiner et al all atom: parm91x.dat + "91" prep files
leaprc.ff94   -- Cornell et al: parm94.dat + 94 prep files
leaprc.ff96   -- Cornell et al: parm96.dat + 94 prep files
leaprc.ff98   -- Cornell et al: parm98.dat + 94 prep files
leaprc.ff99   -- parm99.dat + 94 prep files = parm99 additive, no lone pairs
leaprc.ff02   -- parm99.dat + 00 prep files = parm99, nonadditive, no lone pairs
leaprc.ff02EP -- same as ff00, but with lone pairs, non-additive
leaprc.gaff   -- for organic molecules, with the "general Amber force field"
leaprc.ME     -- from Yong Duan, using solvated charges, new torsions

Above files all assume that nucleic acids by default are DNA.  To assume
RNA, use files with "rna" in the file name.
