Isotopic substitution on g92

 Louis Grace asked,
          As a reference for some benzenoid compounds I'm studying, I'm doing
     ab initio calculations (using Gaussian92) on benzene and benzene-d6.
     I've successfully run the benzene molecule, but when I try a frequency
     calculation on benzene-d6, g92 doesn't seem to like my input file.  It keeps
     giving me "Expecting floating point, found end of line."  Does
 anyone know
     the exact format of an input file for a frequency calculation with isotopic
     substitution (using the keyword, freq=readisotopes) under g92?  Also, my
     benzene molecule was built with a dummy variable in the center, and it is
     the first line in the z-matrix.  Do I just ignore this when putting in my
     isotopic masses?
 The input for Freq=ReadIso consists of one line with the parameters
 for the thermochemistry -- Temperature (Kelvin), Pressure (Atm), and
 (starting with Gaussian 92 Revision D) optionally the scale factor to
 apply to the frequencies.  Zero temperature or pressure defaults to
 the standard values.  A zero scale factor defaults to the recommended
 value of 1/1.12.  Omitting the scale factor or setting it to 1 leaves
 the frequencies unchanged.
 The masses are entered as integers, with one for each atom on a line
 by itself.  Only real (i.e., non-dummy) atoms are specified, as the
 integer values customarily used to refer to the isotopes.  The program
 then uses the corresponding exact value -- for eaxmple, requesting a
 mass of 18 for Oxygen causes the value 17.9915939 to be used.
 Here's a complete input file for water frequencies with the isotopes
 O18, D, and T.  A temperature of 100 Kelvin, 2 atmospheres pressure,
 and the standard scale factor are also requested:
 # rhf/sto-3g freq=readiso
 water
    0   1
  O
  H,1,R2
  H,1,R2,2,A3
  R2=0.98940918
  A3=100.02691259
 100.0 2.0 0.0
 18
 2
 3
 Note that the values printed for the frequencies are the unscaled
 ones, even if the thermochemistry uses scaling.y
 In versions of Gaussian 92 prior to Revision D, the scale factor cannot
 (and should not) be specified.
 Mike Frisch
 frisch (+ at +) lorentzian.com
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