INVESTIGATION OF VAN DER WAALS COMPLEXES IN A FREE EXPANSION OF C 2 H 2 /X (X=RARE GAS) (X=Rg) USING CW CAVITY RING-DOWN SPECTROSCOPY IN THE OVERTONE RANGE

Summary Introduction The Fantasio set-up Challenge(s) Results!!! Next?

Introduction In practice  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr A priori ordering in the interaction energy

Introduction In practice  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Initial experiment Should be observed but expensive Less rigid Too expensive Ordering a priori in the interaction energy

Introduction In practice (Literature)  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Ordering a priori in the interaction energy C2H2C2H2 MWIRNI NeXX ArXXX KrNEVER REPORTED

Introduction  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Ordering a priori in the interaction energy Milce et al, Chem. Phys. Letters, 250 (1996) 95 In practice (Literature) C2H2C2H2 MWIRNI NeXX ArXXX KrNEVER REPORTED

Introduction In practice  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Ordering a priori in the interaction energy Milce et al, Chem. Phys. Letters, 250 (1996) 95 C2H2C2H2 MWIRNI NeXX ArXXX KrNEVER REPORTED

“Fourier trANsform, Tunable diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn” FANTASIO set-up Main features 1 Roots primary pump 2 Turbomolecular pumps 3200CT Continuous supersonic expansion Probes: Cavity ringdown spectroscopy Mass spectrometry FTIR

cavity output mirror cavity input mirror detection system h h Gaz

cavity output mirror cavity input mirror detection system I t =I threshold time (  s) (1/e)I t I  onoff h h Gaz

cavity output mirror cavity input mirror detection system I t =I threshold time (  s) (1/e)I t I  onoff R = %   ~ 120  s 650m under 1 cm long slit h h Gaz

Challenge(s) Hitran simulation of C 2 H 2 absorption spectrum Wavenumber (cm -1 )

Challenge(s) Wavenumber (cm -1 ) Hitran simulation of C 2 H 2 absorption spectrum 2CH 1 + 3

2CH CH  3 Challenge(s) Interaction energy of C 2 H 2 -Ar Hitran simulation of C 2 H 2 absorption spectrum Wavenumber (cm -1 )

2CH CH  3 Interaction energy of C 2 H 2 -Ar Wavenumber (cm -1 ) Result (1) C 2 H 2 -Ar EXPANSION of 1% C 2 H 2 in Ar Hitran simulation of C 2 H 2 absorption spectrum

2CH CH  3 Result (1) C 2 H 2 -Ar Interaction energy of C 2 H 2 -Ar Wavenumber (cm -1 ) EXPANSION of 1% C 2 H 2 in Ar Hitran simulation of C 2 H 2 absorption spectrum

2CH CH  3 Result (1) C 2 H 2 -Ar Interaction energy of C 2 H 2 -Ar Wavenumber (cm -1 ) ZOOM 100X a lot of work EXPANSION of 1% C 2 H 2 in Ar Hitran simulation of C 2 H 2 absorption spectrum

2CH CH  3 Result (1) C 2 H 2 -Ar Interaction energy of C 2 H 2 -Ar Wavenumber (cm -1 ) ZOOM 100X a lot of work EXPANSION of 1% C 2 H 2 in Ar Hitran simulation of C 2 H 2 absorption spectrum

T rotational =9 K Result (1) C 2 H 2 -Ar Lauzin et al, J.Phys.Chem A,1113 (2009) 2361

Result (2) C 2 H 2 -Kr  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr

Result (2) C 2 H 2 -Kr  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Wavenumber (cm -1 )

Result (2) C 2 H 2 -Kr EXPANSION: 99% Ar + 1% C 2 H 2  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Wavenumber (cm -1 )

Result (2) C 2 H 2 -Kr EXPANSION: 88% Ar + 1% C 2 H 2 AND 11% Kr  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Wavenumber (cm -1 )

Result (2) C 2 H 2 -Kr EXP. SPECTRUM SIMULATION C 2 H 2 -Kr EXPANSION: 88% Ar + 1% C 2 H 2 AND 11% Kr PGOPHER SOFTWARE (COLIN WESTERN) Wavenumber (cm -1 )

Result (2) C 2 H 2 -Kr EXP. SPECTRUM SIMULATION C 2 H 2 -Kr EXPANSION: 88% Ar + 1% C 2 H 2 AND 11% Kr PGOPHER SOFTWARE (COLIN WESTERN) Wavenumber (cm -1 ) FIRST DETECTION

Result (2) C 2 H 2 -Kr SIMULATION C 2 H 2 -Kr SIMULATION C 2 H 2 -Ar EXPANSION: 88% Ar + 1% C 2 H 2 AND 11% Kr PGOPHER SOFTWARE (COLIN WESTERN) Wavenumber (cm -1 ) EXP. SPECTRUM FIRST DETECTION

Result (2) C 2 H 2 -Kr SIMULATION C 2 H 2 -Kr SIMULATION BOTH CONTRIBUTIONS EXPANSION: 88% Ar + 1% C 2 H 2 AND 11% Kr FIRST DETECTION PGOPHER SOFTWARE (COLIN WESTERN) Wavenumber (cm -1 ) SIMULATION C 2 H 2 -Ar EXP. SPECTRUM

Result (3) C 2 H 2 -Ne NO SIGNAL  EXPANSION C 2 H 2 IN Ne

Result (3) C 2 H 2 -Ne NO SIGNAL  Increase pressure ratio Decrease slit width EXPANSION C 2 H 2 IN Ne

Result (3) C 2 H 2 -Ne NO SIGNAL  EXPANSION C 2 H 2 IN Ne Increase pressure ratio Decrease slit width

Result (3) C 2 H 2 -Ne NO SIGNAL  Cooling of the slit EXPANSION C 2 H 2 IN Ne Increase pressure ratio Decrease slit width

Result (3) C 2 H 2 -Ne  De C 2 H 2 -Ne C 2 H 2 -Ar C 2 H 2 -Kr Wavenumber (cm -1 )

Result (3) C 2 H 2 -Ne - 4°C 30°C Wavenumber (cm -1 ) Slit temperature

Result (3) C 2 H 2 -Ne ZOOM 5X - 4°C 30°C Wavenumber (cm -1 ) Slit temperature

Result (3) C 2 H 2 -Ne C 2 H 2 -Ne Bemish et al J.Chem.Phys,109 (1998) 8970 C 2 H 2 -Ne?

Result (3) C 2 H 2 -Ne Bemish et al J.Chem.Phys,109 (1998) 8970 C 2 H 2 -Ne C 2 H 2 -Ne?

Result (3) C 2 H 2 -Ne Bemish et al J.Chem.Phys,109 (1998) 8970 C 2 H 2 -Ne C 2 H 2 -Ne? YESSSSSSSSSSSSSS

Perspectives Experimental

Perspectives Experimental PULSED EXPANSION

Perspectives Experimental PULSED EXPANSION Theory Quit the rigid approach And solve numerically This problem

Perspectives Experimental PULSED EXPANSION Theory Quit the rigid approach And solve numerically This problem NEXT TALK

ACKNOWLEDGEMENTS Peter Macko Jean Vander Auwera Athena Rizopoulos Baris Kizil Patrick Van Poucke And you for your attention…

Result (3) C 2 H 2 -Ne ZOOM 5X - 4°C 30°C Wavenumber (cm -1 ) Slit temperature