SYMF 
Interactive ground state fitting
program for symmetric tops

SYMF is adapted from the Sreduction part of
ASFIT, and fits prolate type constants. The
constant sequences necessary to fit h_{3}
doubling in C_{3v} tops, or d_{2}
doubling in C_{4v} tops are
available. Although such issues can be dealt with
using simple closed formulae there are specific
peculiarities in the behaviour of energy levels which
come in near the spherical limit. Diagonalisation of the
Hamiltonian becomes mandatory, as described in connection
with the MMW spectrum of trichloroacetonitrile, for the
analysis of which this program was developed:
G.Cazzoli and Z.Kisiel, J.Mol.Spectrosc. 159,
96102 (1993)
The program can of course also be used even when only the
diagonal constants are necessary, although all asymmetric
top constants up to decadic can be specified. It is up to
the user to set only those constants which are reasonable
for his molecule. Some useful features:
 most interactive features and
cyclic operation as inherited from ASFIT, but
note that several online modifications of
transitions are not available  these have to be
made with an external editor
 central, intensity weighted
frequencies of unresolved pileups for lowest Kvalues
can be fitted
 since calculation is in full
diagonalization it is possible to use only one of
the two components of a splitting pair (such as
for K=3 doubling in a C_{3v}
top)
 if K=3 (or similar)
doubling is not resolved but is suspected of
broadening the observed lines then the mean
frequency of the two components can be fitted
 current limit on J is 250
 new user friendly data file format
available from Feb 2001
 annotations can be placed between
transition declarations, either as alphanumeric
comments, or just spacing lines



SYMF.FOR 
The listing, the extension .SMF
is reserved for the data 
TCAC.SMF 
The data for
trichloroacetonitrile.
 The number of
transitions can be set to some
larger value and the program will
then count the number of
transitions that were actually
found
 The number of
constants is the number of
leading constants in the
Hamiltonian that follow (counting
also the empty line after B)

TCAC.RES 
Results for the above
 note that nearsphericity makes
frequencies sensitive to the value of the
axial rotational constant A 



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SYMTOP 
SYMmetric TOP
ground state predictive program

This is a simple predictive program for ground state,
symmetric top transitions, from constants up to sextic.
The idea of the program was to print out compact
predictions for the heavier symmetric tops which would be
handy during mmwave measurements.
A useful feature of SYMTOP is that it calculates
uncertainties in the predicted transitions from both
uncertainties in the individual constants and (if
available) the correlation matrix  check the
difference...



SYMTOP.FOR 
The listing, the extension .SMT
is reserved for the data 
TBNC.SMT 
The data for tertiary
butyl isocyanide. The input has been
modified for consistency with what I
attempt to preach on this web site 
namely that it should be as
selfdocumenting as possible. 
TBNC.RES 
The results for the
data above, can be compared with J.Mol.Spectrosc.
151, 396 (1992) 



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LFITD 
Fitting of v=1, Estate transitions
in a C_{3v} symmetric
top

LFITD uses the full diagonalization approach although the
complete 2(2J+1) energy matrix is first
factorized into an Asymmetry block and two
degenerate Esymmetry blocks, each ca. 3J/2
in size. The method is well described in K.M.T.Yamada,
M.Bester, M.Tanimoto, G.Winnewisser, J.Mol.Spectrosc.
126, 118 (1987). The J
substate labeling is in terms of Kl1. The
program is related in many ways to ASFIT and SYMF, so
that the mode of operation, internal structure and output
are similar.



LFITD.FOR 
The listing, the extension .LFD
is reserved for the data 
CYANPROP.LFD 
The data for
cyanopropyne, v_{12}=1 from
Yamada et. al. J.Mol.Spectrosc. 126,
118 (1987). 
CYANPROP.RES 
Output for the above 
SID3FV6.LFD 
The MMW data for SiD_{3}F,
v_{6}=1: note the ttype
splitting doublets and the use of
exclusions to predict components 
SID3FV6.RES 
Output for the above:
can be compared with the final results in
J.Mol.Spectrosc. 197,
85 (1999). 



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V2E 
Fitting of v=2, Estate transitions in a C_{3}_{v} symmetric top

V2E is a modification of the program diag3v
written by J.Demaison and used for CD_{3}CN. The
approach is to fit the v^{l} = 2^{0}
and 2^{2} states simultaneously by using the
additional l dependent terms X_{ll}
and B_{3}  see J.Cosleou, G.Wlodarczak,
J.Burie, J.Demaison, J.Mol.Spectrosc. 137,
47 (1989). The quantisation is J, K,
l, where K and l are signed
quantities. The program will also work for the v=1
state, since all the necessary constants are already
there.
The program embodies various useful statistical tests
that have so far seen relatively little application in
rotational spectroscopy  for explanation see J.Demaison,
J.Cosleou, R.Bocquet, A.G.Lesarri, J.Mol.Spectrosc.
167, 400418 (1994).



V2E.FOR 
The listing, the data is
expected to be in file V2E.INP and the
output is written to file V2E.OUT 
CD3CN.INP 
Partial data set for
CD3CN, v_{8}=2: only the J=12
frequencies from J.Mol.Spectrosc.
137, 47 (1989) are put
in 
CD3CN.OUT 
Output for the above,
with prediction of unreported frequencies
for this J 



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