1. High Resolution Measurements and Electronic Structure Calculations of a Diazanaphthalene: [1,6]-naphthyridine. Sébastien Gruet, Manuel Goubet, Olivier Pirali ISMS 2014 17/06/2014

2. 2 Structure of small PAHs molecules Complementarity of MW and IR data Principal sources of rotational informations (GS) – Microwave spectroscopy – UV for centrosymmetric molecules Y. Semba et al. J. Chem. Phys. 131, 024303 (2009) Publications of high resolution IR data are scarce S. Albert et al. Faraday Discuss. 150, 71-99 (2011) B. E. Brumfield et al. J. Phys. Chem. Lett. 3, 1985-1988 (2012) O. Pirali et al. PCCP, 15, 10141-10150 (2013) Rotational resolved data in the Literature Hypothesis A. Leger, J. L. Puget, A&A 1984, 137, L5. Peeters et al, 2002, A&A,390, 1089

3. Mid- & Near Infrared (Classical Sources) Mid- & Near Infrared (Classical Sources) 3 (372) 3000 (372) 3000 1000 (62) 500 (62) 500 (12) 100 (12) 100 (1.2) 10 (1.2) 10 6000 30 250 750 Far-Infrared The AILES Beamline (Synchrotron Radiation) Far-Infrared The AILES Beamline (Synchrotron Radiation) Fundamental vibrational modes of PAHs (meV) cm -1 Room temperature long pathlength cell Optical pathlength : 150 m Spectral range : 30 – 1000 cm -1 Resolution : 0.00102 cm -1 ≈ 30 MHz Spherical moving mirror MW Radiation Gas injection L-shaped antenna Vacuum : ≈ 10 -6 mbar Step by step motor Stainless steel cell Spherical mirror (Aluminum) Pumping group Pulsed nozzle Gaussian beam profile W 0 = 42 mm à 12 GHz 1200 mm Supersonic Jet Set-up of the FT-MW spectrometer Spectral range : 4 – 20 GHz ≈ 0.13 – 0.67 cm -1 Resolution : 1.8 kHz ≈ 6.10 -8 cm -1 MicroWave The PhLAM Laboratory (Electronic sources) MicroWave The PhLAM Laboratory (Electronic sources) Pure Rotational Transitions of PAHs 0 0 1 1 (0.06) 0.5 (0.06) 0.5

4. 4 Pure Rotational Spectrum PhLAM Laboratory Pure Rotational Spectrum PhLAM Laboratory Ro-vibrational Spectrum AILES Beamline Ro-vibrational Spectrum AILES Beamline

5. c b 5 Infared transitions Out of plane vibrational modes c a b μ a = 1.55 D μ b = 0.46 D Microwave transitions a-type b-type + hyperfine structure c-type

6. Collaboration with M. Goubet from the PhLAM laboratory at Lille 6 Spherical moving mirror MW Radiation Gas injection L-shaped antenna Vacuum : ≈ 10 -6 mbar Step by step motor Stainless steel cell Spherical mirror (Aluminum) Pumping group Pulsed nozzle Gaussian beam profile W 0 = 42 mm à 12 GHz 1200 mm Supersonic Jet

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8. 8 [1,6]-naphthyridine Par. GS (Combined fit: MW + IR data) ν 38 ν 34 Band Center MHz/cm -1 14490562.34(45) /483.353132(15) 25247267.84(47) /842.158205(16) A3227.104274(70)3226.28045(68)3225.90185(54) B1276.297178(30)1276.1874(40)1276.09822(73) C914.802113(21)915.1597(57)914.8647(12) Δ J.10 3 0.01973(11)0.01953(12)0.01973 c Δ K.10 3 0.16660(89)0.16524(96)0.16660 c Δ JK.10 3 0.04866(58)0.04954(66)0.04866 c δ J.10 6 5.598(61)5.598 c δ K.10 6 70.4(16)70.4 c χ aa (N1)1.5191(18) χ bb (N1)-4.6809(12) χ aa (N6)-3.6392(15) χ bb (N6)0.2234(17) N lines28027802460 MW/IR RMS0.002665 MHz0.00020 cm -1 J”2-1715-9915-83 Ka”Ka”0-614-6114-41

9. 9 Anharmonic DFT calculation at the B97-1/cc-pVTZ//ANO-DZP level Accurate calculated rotational parameters More details about calculations: M. Goubet, O. Pirali, J. Chem Phys. 140, 044322 (2014) Useful tool to begin the GSCD analysis by LWW diagram [1,6]-naphthyridine ModeGS 38 34 ParametersCalculatedExperimentalDeviationCalculatedExperimentalDeviationCalculatedExperimentalDeviation A /MHz3227.5955823227.104274-0.4913083226.486353226.28045-0.205893226.18655583225.90185-0.28470 B /MHz1274.8374481276.2971781.4597301274.777491276.18741.409911274.7475111276.098221.35070 C /MHz914.0971837914.8021130.704929914.4269554915.15970.73274914.1271629914.86470.73753 Anharmonic DFT calculation at the B97-1/cc-pVTZ//ANO-DZP level Corrected Calculated Values ExperimentalDeviation Corrected Calculated Values ExperimentalDeviation 3225.995043226.280450.285413225.695253225.901850.20660 1276.237221276.1874-0.049821276.207241276.09822-0.10902 915.13188915.15970.02782914.83209914.86470.03261

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11. Combining MW and FT-FIR data: – Excited states of small PAHs and derivatives FA09 – Roger Adams Lab 116 – 11 h 01 to 11 h 16 AM – Spectroscopy of diamond-like and biphenyl-like molecules 11 Important database of rotational information in the IR  Simulation at different resolution and at low temperature Pure carbonated PAHs PANHs (PAHs with nitrogen atoms)