DETAILED ANALYSIS OF THE INFRARED SPECTRUM OF SiF4: AN UPDATE
VINCENT BOUDON, Laboratoire ICB, CNRS/Universite´ de Bourgogne, DIJON, France; LAURENT
MANCERON, Synchrotron SOLEIL, CNRS-MONARIS UMR 8233 and Beamline AILES, Saint Aubin,
France.
 !"
 !#
$!"
$!#
#!"
#!#
%
&
'
(
)
&
*
+
,
-
.$#.##/0#/1#/2#
3*4-+56&-)787,6
9$
:;<-)=6-+>
?@(&*@7'=65@*>=(+7A7$B#7C
 1
D=E
.
 0
D=E
.
/#
D=E
.
/11!0/11!1/11!2/11!B/11!"
3*4-+56&-)787,6
9$
 1
D=E
.
7 7&)*+,F
Silicon tetrafluoride (SiF4) should be a normal trace component of volcanic
gases. However, a better knowledge of spectroscopic parameters is needed for this
molecule in order to derive accurate concentrations.
As explained last year, we undertook an extensive high-resolution study of
its infrared absorption bands, for the there isotopologues in natural abundance:
28SiF4 (92.23 %), 29SiF4 (4.67 %) and 30SiF4 (3.10 %). We present here an up-
date of this study. It includes a new global fit with consistent parameter sets for the
ground and excited states (the Figure on the right presents the 4 bending funda-
mental region). In particular, all existing rotational line data have been included.
The 24 band of 28SiF4 could also be analyzed in detail. A first rough estimates
of the dipole moment derivative for the 3 band has been performed, leading to
to an integrated band intensity which is consistent with literature values, around
680 km=mol. The isotopic dependance of band centers and Coriolis parameters has been studied, thanks to the formula
presented in talk P4363.