  Methanol is observed in a wide range of astrophysical sources throughout the
universe, and comprehensive databases of the millimeter and THz spectra of
CH3OH and its principal isotopologues represent important tools for the
astronomical community. A previous combined analysis of microwave and
millimeter wave spectra of 13CH3OH together with Fourier transform far-infrared
spectra was limited to the first two torsional states, v_t = 0 and 1, for J
values up to 20. The limits on frequency and quantum number coverage have
recently been extended by new millimeter and THz measurements on several
different spectrometers in the Cologne laboratory in the frequency windows
34-70 GHz, 75-120 GHz, 240-340 GHz, 360-450 GHz and 1.12-1.50 THz. With the new
data, the global treatment has now been expanded to include the first three
torsional states for J values up to 30. The current 13CH3OH data set contains
about 2,300 microwave, millimeter-wave, sub-millimeter and THz lines and about
17,100 Fourier-transform far-infrared lines, representing the most recent
available information in the quantum number ranges J </= 30, K </= 13 and v_t
</= 2. The transitions have been successfully fitted to within the assigned
measurement uncertainties of +/-50 kHz for most of the frequency-measured (i.e.
MW, MMW, Sub-MMW, THz) lines and +/-6 MHz for the FIR lines. A convergent
global fit was achieved using 103 adjustable parameters to reach an overall
weighted standard deviation of 1.37. Our new C-13 methanol database is improved
substantially compared to the existing one (Li-Hong Xu, F.J. Lovas, J. Phys.
Chem. Ref. Data 26 (1997) 17-156), and will be available in the Cologne
Database for Molecular Spectroscopy, CDMS (http://www.astro.unikoeln.de/cdms/).
(Abbreviated)
