1. Determination of succinic acid structure in the gas phase by cm/mm spectroscopy Estíbaliz Méndez Alija University of The Basque Country, UPV/EHU, Spain

3. Spectrometers

4. LEIBNIZ UNIVERSITÄT HANNOVER GERMANY Resolution: 3kHz Range: 2 – 26 GHz Gas Phase Generation: heating (180 o C) High Resolution Pulsed Fourier Transform Microwave Spectrometer Rev. Sci. Instr, 67, (1996), 4072

5. MONASH UNIVERSITY MONASH AUSTRALIA Resolution: 100 – 200 kHz Range: 48 – 70 GHz Gas Phase Generation: heating (180 o C) Free Jet Stark Modulated Spectrometer J. Mol. Struct, 190, (1988), 185-193

6. UNIVERSITY OF THE BASQUE COUNTRY BILBAO SPAIN Resolution: 3kHz Range: 4 – 18 GHz Gas Phase Generation: Ultrafast UV laser ablation system Nd-YAG 355 nm 3 mJ/pulse High Resolution Pulsed Fourier Transform Microwave Spectrometer PCCP, 12, 12486 - 12493, 2010

7. Quantum Methods: MP2, M06-2X, B3LYP Basis Sets: cc-pVTZ, 6-311++g(d,p) MP2/6-311++g(d,p) Z E ZZ

8. Frequency (MHz) Experimental Ab initio Q-branch transitions

10. D (O-D) ( 0.015%) Parent 13 C ( 1.1%) 5 0,5 4 1,4 18 O ( 0.20%) 3 1,3 2 0,2

12.  (H 9 -O 7 -C 4 -O 6 ) = - 179(1)º  (O 6 -C 4 -C 1 -C 2 ) = 171(12)º  (C 1 -C 2 -C 3 -C 4 ) = 110(14)º  O 5 -C 3 -C 2 -C 1 ) = 171(1)º  O 5 -C 3 -O 8 -H 10 ) = - 179(11)º r(C 1 -C 2 )=1.49(82) Å r(C 4 -C 1 )=1.48(14) Å r(C 3 -O 5 )=1.23(12) Å r(C 4 -O 7 )=1.36(03) Å r(O 8 -H 10 )=0.95(13) Å Substitution Structure 4 1 2 3 5 8 10 6 7 9  (H 9 -O 7 -C 4 )=109(7)º  (O 6 -C 4 -C 1 )=126(3)º  (C 1 -C 2 -C 3 )=112(3)º  (O 5 -C 3 -C 2 )= 126(3)º  (O 5 -C 3 -O 8 )= 121(10)º

13. CONCLUSIONS Gauche conformation about central carbons Z conformations of carboxylic groups No intramolecular hydrogen bonds

14. Michaela K. Jahn K.P.Rajappan Nair Prof. Jens-Uwe Grabow Michaela K. Jahn K.P.Rajappan Nair Prof. Jens-Uwe Grabow Peter D. Godfrey Prof. Don McNaughton Peter D. Godfrey Prof. Don McNaughton Dr. Patricia Écija Dr. Emilio J. Cocinero Prof. Fernando Castaño Dr. Francisco J. Basterretxea Dr. Patricia Écija Dr. Emilio J. Cocinero Prof. Fernando Castaño Dr. Francisco J. Basterretxea