To perform an MP2 calculation of the NMR shieldings you have to prepare the input with mp2prep -c.
mpshift will then calculate both the SCF and MP2 shielding constants. The result is written into the control file after the keyword $nmr mp2 shielding constants.
The script mp2prep will create the keywords
$csmp2 $thize .10000000E+10 $mointunit type=intermed unit=61 size=0 file=halfint type=1112 unit=63 size=0 file=moint#1 type=1122 unit=64 size=0 file=moint#j type=1212 unit=65 size=0 file=moint#k type=1212a unit=70 size=0 file=moint#a type=gamma#1 unit=71 size=0 file=gamma#1 type=gamma#2 unit=72 size=0 file=gamma#2 type=dtdb#1 unit=76 size=0 file=dtdb#1 type=dtdb#2 unit=77 size=0 file=dtdb#2 $traloop 1 $statistics mpshiftand starts a statistics run of mpshift (by calling mpshift). If the resulting disk space requirement exceeds the automatically detected free disk space on your system, it will increase
$traloopand run a statistics run again. This will be done as long as your free disk space is not sufficient for the calculation.
If the mp2prep script fails to run on your system, try to use
the -p option or do the procedure described above by hand. Call
mp2prep -h for more informations about mp2prep.