modes {<modes-statement>} end

<modes-statement> :==
   
  {<modes-group-statement>}
  temperature=<real>
  --{Reference temperature for frequencies in Kelvin.}
  qprint=<logical>
  --{Print eigenvectors.}

  <modes-group-statement> :==

    group=<atom-selection> nmode=<integer>
    --{Atom selection for mode calculation and the number of modes to be
       calculated for this selection.}
    foutput=<filename>
    --{Frequency output file.}
    eoutput=<filename>
    --{Eigenvector output file.}
    coutput=<filename>
    --{Nominal (average) coordinate output file.}
    moutput=<filename>
    --{Mode output file.}
    <trajectory-statement>

    --{Within a group the following is calculated between all atoms:
         s[i,j]=<D[i]*D[j]>
       where D is the coordinate displacement with respect to the average
         D={(x1,y1,z1),(x2,y2,z2),.....(xn,yn,zn).}

    <trajectory-statement> :==

      input=<filename>
      --{File to read trajectory from.}
      begin=<integer>
       --{Start at this step in trajectory file. Default=1}
      skip=<integer>
      --{Skip the specified number of steps. Default=1}
      stop=<integer>
      --{Stop at this step. Default=999999}
      ascii=<logical>
      --{Input trajectory is formatted rather than binary. Default=false}

      --{Several input files may be specified. Files are read in the
         order given. Begin, skip, stop are all in integration units.}