\\ Species Tag:        &   60003 & Name:&  CH3OCHO
\\ Version:            &       1 & & Methyl Formate,
\\ Date:       &  April 2009     & & v$_T$ = 0,1
\\ Contributor:&  B.J. Drouin    & & A, E states  
\\             &                 & &
\\ Lines Listed:       &   61521 & Q(300.0)=&   199602.70
\\ Freq. (GHz) $<$     &    1699 & Q(225.0)=&   121102.02
\\ Max. J:             &      69 & Q(150.0)=&    59072.96
\\ LOGSTR0=            &    -9.0 & Q(75.00)=&    17548.82
\\ LOGSTR1=            &    -7.0 & Q(37.50)=&     5772.42
\\ Isotope Corr.:      &     0.0 & Q(18.75)=&     2030.84
\\ Egy. (cm$^{-1}$) $>$&     0.0 & Q(9.375)=&      720.82
\\ $\mu_a$ = & 1.63              & A=&17629.81
\\ $\mu_b$ = & 0.68              & B=& 9243.30
\\ $\mu_c$ = &                   & C=& 5318.39
\headend
 
The data set used is from V. Ilyushin A. Kryvda, E. Alekseev, J. Mol. Spectrosc. 255 (2009) 32-38 and includes data from \\
R.D. Brown, J. G. Crofts, F.F. Gardner, P.D. Godfrey, B.J. Robinson, J.B. Whiteoak, Astrophys. J. 197 (1975) L29-L31.\\
A. Bauder, J. Phys. Chem. Ref. Data 8 (1979) 583-618.\\
J. Demaison, D. Boucher, A. Dubrulle, B. P. Van Eijck, J. Mol. Spec, 102 (1983) 260-263.\\
G.M. Plummer, G.A. Blake, E. Herbst, F.C. DeLucia, Astrophys. J. Supl. Ser. 55 (1984) 633-656.\\
G.M. Plummer,  E. Herbst, F.C. DeLucia, G.A. Blake, Astrophys. J. Supl. Ser. 60 (1986) 949-961.\\
L.C. Oesterling, S. Albert, F.C. DeLucia, G.A. Blake, Astrophys. J. 521 (1999) 255-260.\\
Y.Karakawa, K. Oka, H. Odashima, K. Takagi, S. Tsunekawa, J. Mol. Spectrosc. 210 (2001) 196-212.\\
H. Odashima, K. Ogata, K. Takagi, S. Tsunekawa, Molecules 8 (2003) 139-145.\\
K. Ogata, H. Odashima, K. Takagi, S. Tsunekawa, J. Mol. Spectrosc. 225 (2004) 14-32.\\
M. Carvajal, F. Willaert, J. Demaison, I. Kleiner, J. Mol. Spectrosc. 246 (2007) 158-166.\\
A. Maeda, I.R. Medvedev, F.C. DeLucia, E. Herbst, P. Groner, Astrophys. J. Supp. Ser. 175 (2008) 138-146.\\
A. Maeda, I.R. Medvedev, F.C. DeLucia, E. Herbst, J. Mol. Spectrosc. 251 (2008) 293-300.\\
As indicated by the authors only lines with rms > 400 kHz were excluded from the analysis (about 50 assignments). An internal rotor Hamiltonian, based on the \lq\lq $\rho$ axis method", similar to that developed for this species byIlyushin and Carvajal, was utilized for fitting of the torsion-rotation spectrum.  A primary difference in the analysis regards the usage of the internal rotation operator, $p$, in IAMCALC/SPFIT the operator always appears as $\tilde{p}$ = $p$ + $\rho P_a$ whereas Kleiner's program uses this combination only in the definition of $F$ and simply uses $p$ in all other operator definitions.  The program IAMCALC utilises the Mathieu function to generate an extensive set of linked parameters that connect torsional levels (v$_T$ = 0-1, $A,E$) defined as per the table below.  Additional levels up to v = 20 (v$_T$ = 6) were utilized for the basis set, these levels do not accurately describe higher torsional levels due to their position near or above the barrier to internal rotation, therefore predictions are truncated at the 1$^{st}$ torsional level.  The dipole moment components specified in the \lq .int' file are given in the $\rho$ axis system and are equivalent to principle axes values upon rotation.  The rotational constants given here have been rotated from the $\rho$ axis system using $D_{ab}$ to obtain principle axis values.  The data analysis extends to $J$ = 62 and fits data to experimental precision.  The calculation is extended to $J$ = 69 .  The partition function was determined in a separate calculation in which the maximum $J$ was extended to 109.  Test calculations with larger maximum $J$ values were unchanged, indicating good convergence.  Note that this partition function implicitly includes the ground and first torsional levels, thus representing a partial vibrational partition function.


The dipole moments are from R. F. Curl, Jr., 1959, J. Chem. Phys. {\bf
30}, 1529.

\begin{table}[h]
\begin{tabular*}{\hsize}{@{\extracolsep{\fill}}c|c|c|c}
    & gs   &  v$_T$ = 1 \\
\hline
A  & 0    &   3        \\
E  & 1,2  &   4,5      \\
\end{tabular*}
\end{table}