The Microwave Spectrum of the Mono Deuterated Species of Methyl Formate HCOOCH 2 D L. H. Coudert, a L. Margulès, b G. Wlodarczak, b and J. Demaison b a LISA, CNRS/Paris 12 University, Créteil, France b PhLAM, CNRS/Lille I University, Villeneuve d’Ascq, France
Overview The normal species The data Mono deuterated species PEF Energy level calculation Analysis results
The normal species It is a molecule of astrophysical interest which has been the subject of many investigations. Non-rigid molecule displaying internal rotation of the methyl group transitions measured for the A and E-species up to J 62 and within v t 0 and 1. The barrier to internal rotation is V 3 = 370 cm
PEF of the mono deuterated species HCOOCH 3
HCOOCH 2 D 10 cm
Tunneling sublevels HCOOCH MHz HCOOCH 2 D 81.8 MHz ~10 cm For J 0, the rotational dependence of the tunneling splitting must be taken into account. The IAM water dimer 1 formalism will be used. 1. Hougen, J. Mol. Spec. 114, 395 (1985) & Coudert and Hougen, J. Mol. Spec. 130, 86 (1988)
eq eq eq h 2, 2, 2, 2 h 0, 0, 0, 0
ParametersNumberRelation h 2, 2, 2, 2 3 2 2 h 0, 0, 0, 0 0not used A, B, C3D in plane A, B, C3D out of plane Spectroscopic parameters 9 zeroth order parameters
Rotational dependence of the tunneling J 0,J J 2,J 2 J 4,J 4 J 6,J 6 J 8,J 8 J 10,J 10 J 12,J 12
Rotational dependence of the tunneling J 1,J J 3,J 2 J 5,J 4 J 7,J 6 J 9,J 8 J 11,J 10 J 13,J 12
Rotational dependence of the tunneling High K c -values, tunneling depends on K c only
The data RangeUncertainty NTechnique 7 to 70 GHz150 kHz 352Stark 150 to 650 GHz 30 kHz1126BWO Max J is 61, max K a is a-type and 435 b-type with v 0
Analysis results Data NRMS 7 to 70 GHz MHz 150 to 650 GHz MHz All MHz Unitless standard deviation is 4.3
Spectroscopic parameters D out of plane configurations
2 and 2 calculation 1. Hougen, J. Mol. Spec. 114, 395 (1985) & Coudert and Hougen, J. Mol. Spec. 130, 86 (1988) Values for 2 and 2 can be calculated from the geometry of the molecule along the tunneling path. 1
Tunneling splitting rotational dependence Using the structure of Curl: 1 1. Curl, J. Chem. Phys. 30, 1529 (1959)