Microwave spectrum of furfuryl alcohol Roman A. Motiyenko, Manuel Goubet, Thérèse R. Huet, Laurent Margulès, Georges Wlodarczak PhLAM Laboratory, University Lille 1, Villeneuve d’Ascq, France Eugen A. Alekseev Institute of Radio Astronomy of NASU, Kharkov, Ukraine

Motivation Ribose furfural furfuryl alcohol 2-furoic acid R. Motiyenko et al. JMS, vol. 240, pp JMS, vol. 244, pp decomposition products:

Furfuryl alcohol skew 1 (E=210 cm -1 ) skew 2 (E=700 cm -1 ) skew 3 (E=0 cm -1 ) syn 1 (E=42 cm -1 ) syn 2 (E=409 cm -1 ) K.M. Marstokk and H. Mollendal, Acta Chemica Scandinavica, vol. 48, pp. 25 – 31 (1994) Microwave measurements in 26 – 39.5 GHz frequency range and ab initio calculations at MP2/6-31G* level Previous study:

Experimental setup o FTMW spectrometer in Lille (4 – 20 GHz) o Microwave spectrometer in Kharkov (60 – 150 GHz, measurement precision: 0.01 MHz) o Microwave spectrometer in Lille (150 – 210 GHz, measurement precision: 0.02 MHz) Computational details: o ab initio calculations at MP2 level with: G(3df,2p) aug-cc-pVTZ cc-pVQZ basis sets

MWFT results In pulsed jet MWFT experiments with Ne as a carrier gas skew 3 was the only conformer observed. This can be explained by effective relaxation of skew 1 into skew 3 during supersonic expansion Calculated ab initio value of barrier height to OH torsion between skew 1 and skew 3 is 320 cm -1 and thus suggests the relaxation in jet with Ne ( R.S.Ruoff, T.D.Klots, T. Emilsson and H.S. Gutowsky, J.Chem.Phys. vol. 93, pp – 3150 (1990) ) skew 1skew 3

Conventional spectroscopy J=25 ← 24 a R 0,1 Excited vibrational states should be also studied! Ka=Ka= Ka=Ka=

Excited vibrational states skew 1skew 3 ring–CH 2 OH torsion ring–CH 2 OH bending OH torsion Low-frequency (cm -1 )

Assignment strategy skew 1: μ a =1.6 D skew 3: μ a =1.5 D J+1 1,J+1 ← J 1,J J+1 0,J+1 ← J 0,J J+1 0,J+1 ← J 1,J J+1 1,J+1 ← J 0,J μ b =1.6 D J=25 ← 24

Summary of results skew 3 skew 1 Nσ (MHz) J max K a max Nσ (MHz) J max K a max v= v t = v t = v t = v b = v OH = v t =1,v b = v t =2,v b = skew 1 v t =1 OldNew A (MHz) (48) (22) B (MHz) (11) (41) C (MHz) (10) (44)

Ab initio calculations Skew 1Skew 3 A (MHz) B (MHz) C (MHz)  a (Deb.)  b (Deb.)  c (Deb.) A (MHz) B (MHz) C (MHz)  a (Deb.)  b (Deb.)  c (Deb.) MP2/ G(3df,2p) MP2/ aug-cc-pVTZ MP2/ cc-pVQZ Exp Energies calculated using MP2/aug-cc-pVTZ and G3 methods (cm -1 ) Rotational constants and dipole moments skew 3 skew 1 (MP2) skew 1 (G3) syn 1 (MP2) Transition state (skew1-skew3) D1D3 E E-ZPE

Perturbations K a = E over ZPE (cm -1 ) v t =1 v t =2 v b =1 v t =3 v t =1, v b =1 K a =21 K a =19 v OH =1 K a =14 v t =4 v t =2, v b =1 v b =2 K a =8 K a =9 K a =17 v=0 v t =1 v b =1 v t =2 up to K a =3 v=0 skew 3 skew 1 from previous study: ΔE=125(33) cm -1

New software

Acknowledgements Dr. Jean Demaison Dr. Vadim Ilyushin INTAS foundation (YSF ref. n )