Description of supplementary material for the article: 

"Investigations into the rotational spectrum of isotopic methyl mercaptan,
 13CH3SH, in the laboratory and towards Sagittarius B2(N2)"

by V. Ilyushin, O. Zakharenko, F. Lewen, S. Schlemmer, E.A. Alekseev,
   M. Pogrebnyak, R.M. Lees, L.-H. Xu, A. Belloche, K.M. Menten,
   R.T. Garrod, and H.S.P. Müller


The supplementary material is in the form of four files, ReadMe.txt (this file),
input.txt, output_13CH3SH.txt, and Table_S1S2.txt, which contain the following
tables:


Table S1. Torsion-rotation part Qrt(T) of the total internal partition function
          Q(T)=Qv(T)*Qrt(T), calculated from first principles for 13CH3SH using
          the parameter set of Table 2.

Table S2. A list of calculated positions and assignments of rotational
          transitions in the vt=0,1,2 torsional states of 13C methyl mercaptan
          up to J=60 in the 1 - 1500 GHz frequency range.

Description of file:
  input.txt

  The first 4 lines contain information about the operating mode of the program.
  The next 6 lines remind the user of the format of the Hamiltonian parameters.
  Then the list of parameters used in the fit is given. The line &&&END,,,,,,,,,
  signals the end of this list. The parameter values are given in cm^-1^.
  Each line with a Hamiltonian parameter contains the parameter name, a set of
  7 integers that define the associated quantum mechanical operator, a value for
  the parameter (i.e., for the coefficient of this operator), the
  diagonalization stage in which the particular parameter is used, and a
  float/fix flag.
  The actual term is encoded by the set of 7 integers, which are
  the powers of operators from the Hamiltonian expression. Thus:
  k - (the first integer) corresponds to the power of J**2,
  n - (the second integer) corresponds to the power of Jz,
  p,q - are powers of Jx, Jy,
  r - is the power of pa,
  s - (the sixth integer) defines the argument of cos(3sa),
  t - (the seventh integer) defines the argument of sin(3ta).
  The next 7 lines contain the information necessary for the fitting process and
  the predictions calculation.
  Then the list of measured transition frequencies is given.
  First a measured frequency is given. Then the assignment quantum numbers are
  given. They are followed by the include/exclude switch 'ifit' and by the
  measurement uncertainty. After that space for a comment is reserved.
  The assignment consists of m, J, Ka, Kc quantum numbers. First the upper level
  is given then the lower level is given. The labelling procedure in the program
  determines from the eigenvector composition the levels which belong to each
  particular m-state and then assigns Ka,Kc labels within each m state according
  to the usual asymmetric top energy ordering scheme.

Description of file:
  output_13CH3SH.txt

  The output file is organized as follows. First the initial values of
  parameters as well as different statistics on the experimental data (number
  of transitions, number of blended transitions, number of levels included in
  the fit etc.) are given. Then, for each iteration, the information on the
  parameter changes and current rms deviation for different groups of data are
  given. Then the list of the parameter values for the next iteration is
  presented in the format suitable for the input file (so it can be copied and
  pasted easily to the input file).
  When the fit has converged or the maximum allowed number of iterations has
  passed the output of obtained results is given. The list of transitions with
  J<Jmax from the input file is given three times.
  First it is given in order of frequency, second it is given in the order it
  appears in the input file, and third it is given sorted by spectroscopic
  branches. In these lists the assignments of the levels are augmented by the
  symmetry species labels from the G6 group. When the list of transitions is
  presented sorted by branch the expectation value of the (23)* operation is
  given and also if the transition is blended you will find in the end of the
  line the letter 'b' with the residual calculated from the special treatment
  of blends.


  Detailed explanations on RAM36 could be found at
    http://www.ifpan.edu.pl/~kisiel/introt/ram36/readmeram36.pdf


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