Synchrotron-Based High Resolution Spectroscopy of N-Bearing PAHs

Sébastien Gruet, Olivier Pirali, Manuel Goubet and P. Bréchignac

ISMS 2014

16/06/2014

2

Astrophysical Background

• Hypothesis : A. Leger, J. L. Puget, A&A 1984, 137, L5.

• Typical vibrational modes of aromatic compounds: (in µm) at : 3.3 , 6.2, 7.7, 8.6, 11.3, 20.8, 27 and 56.(in cm-1) at ≈: 3030, 1612, 1298, 1162, 884, 480, 370, and 178.

Naphthalene

Quinoline

Isoquinoline

Quinoxaline

[1,6] Naphthyridine Quinazoline

[1,5] Naphthyridine

N-Bearing PAHs

Peeters et al, 2002, A&A,390, 1089

Rotationally resolved IR data of PAHs in the literature• Relatively recent and still scarce• One of the first publication:S. Albert et al. Faraday Discuss. 150, 71-99 (2011)

TA11 – Roger Adams Lab 116 – 11h35 to 11h50 AM

Quinoline/Isoquinoline: Z. Kisiel et al. J. Mol. Spectrosc. 217, 115 (2003).Quinoxaline/Quinazoline: D. McNaughton, J. Chem. Phys. 124, 154305 (2011)

3

The AILES Beamline at SOLEIL

Experimental deviceRoom temperature long pathlength cell

(150m)Bruker IFS 125Resolution: 0.00102cm-1 ≈ 30MHz

0

Mid- & Near Infrared (Classical Sources)

(372)30001000

(62)500

(12)100 600030 250 750

Far-Infrared The AILES Beamline

(Synchrotron Radiation)

Fundamental vibrational modes of PAHs

(meV)cm-1

Beamline optimized for photons in the 10-1500cm-1 spectral range

4

Experimental Ro-vibrational Spectra (LR & HR)

Resolution: 0.5cm-1

Quinoline

Isoquinoline

Quinoxaline

Quinazoline

[1,5] Naphthyridine

41 37

4541

2827

38

28 41

5

Experimental Ro-vibrational Spectra (LR & HR)

Quinoline

Isoquinoline

Quinoxaline

Quinazoline

[1,5] Naphthyridine

Resolution: 0.00102cm-1

ButterflyMode

DrumheadMode

C-H oopMode

28

41

18

6

Spectroscopy for Asymmetric Top Molecules

Effective Hamiltonian for asymmetric top molecules :

Study of the out of plane vibrational modes :

Selection rules for c-type transitions :

𝐻=(𝐵+𝐶 )

2�̂�2+[𝐴− (𝐵+𝐶)

2 ] �̂� 𝑧2+(𝐵−𝐶)( �̂� 𝑥

2− �̂�𝑧2)

2−∆ 𝐽 �̂�

4−∆ 𝐽𝐾 �̂�2 �̂�𝑧2−∆𝐾 �̂� 𝑧

4−𝛿𝐾 [ �̂�𝑧2 , �̂�𝑥2− �̂� 𝑦

2 ]+¿−2 𝛿 𝐽 �̂�2( �̂� 𝑥

2− �̂� 𝑦2)¿

Quantum numbers :

Butterfly mode at ≈ 170 cm-1

ca

b

c

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Analysis of the IR Data

• Thousands transitions assigned ( 2472 for 28 of Quinoxaline) 28 : and

• Use of the LWW software. Graphical search of transitions and quick assignment

• A few transitions still unassigned. Hot bands sequences

Quinoxaline

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Molecules Isoquinoline Quinoline Quinoxaline Quinazoline [1,5]-naphthyridineParameters ν41 ν37 ν45 ν41 ν28 ν27 ν38 ν22 ν18

Band Centercm-1/MHz

479.485171(14)/14374603.79(41

)

824.847928(20)/24728318.78(60

)

168.42685(17)/5049295.00(45)

476.29985(12)/14279110.35(37

)

177.012852(23)/5306711.82(71)

399.989736(7)/11991390.62(21

)

484.246528(17)/14490568.27(45

)

166.238827(12)/4983714.66(37)

817.836519(14)/24518122.03(41

)A /MHz 3198.15593(57) 3198.07100(99) 3141.720(10) 3145.60425(49) 3159.7236(10) 3163.66994(17) 3229.17317(69) 3168.8103(22) 3166.2677(22)

B /MHz 1237.90868(25) 1237.80930(90) 1271.9964(10) 1271.4866(21) 1311.5359(21) 1310.8785(11) 1276.0753(61) 1311.9904(52) 1311.7859(47)

C /MHz 893.0982(36) 892.8501(13) 906.4591(11) 906.0809(31) 928.0085(32) 927.4615(16) 915.3788(85) 929.0061(52) 928.3064(40)

ΔJ /kHz 0.01874(57) 0.01826(39) 0.0191578(70) 0.019020(78) 0.018624(53) 0.01738(11) 0.01516(19) 0.019731(56) 0.022130(60)

ΔK /kHz 0.15373(33) 0.16758(44) 0.08477(12) 0.16045(32) 0.1557 0.1557(89) 0.14871(67) 0.17964(62) 0.15799(49)

ΔJK /kHz 0.04818(26) 0.04760(19) 0.056525(78) 0.04765(28) 0.03077(38) 0.06348(58) 0.07129(70) 0.04967(37) 0.04563(28)

δJ /kHz 0.005454* 0.005454* 0.00596593(62) 0.005662* 0.005621* 0.005621* 0.005752* 0.005862 0.005862

δK /kHz 0.061465* 0.061465* 0.0593144(76) 0.060622* 0.063420* 0.063420* 0.063307* 0.061291 0.061291

N of lines 2775 2357 2578 2663 2472 2550 2092 2469 1959

IR RMS 0.00016 cm-1 0.00024 cm-1 0.00020 cm-1 0.00017 cm-1 0.00019 cm-1 0.0018 cm-1 0.00021 cm-1 0.00015 cm-1 0.00019 cm-1

J”min/J”max 14/99 17/87 15/94 15/99 12/99 15/83 17/99 9/99 11/91

Ka”min/Ka”max 14/64 17/43 14/50 14/60 12/48 14/41 17/52 9/51 9/51

Results of the fits

• 9 rovibrational bands analyzed for these 5 molecules.

• Analysis of 3 other bands in progress.

• Determination of the GS constants of the [1,5]-napthyridine.[1,5] Naphthyridine

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•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

Electronic Calculations as supporting tools

Quinoxaline

Mode GS 27

Parameters Calculated Experimental Deviation Calculated Experimental Deviation

A /MHz 3166.07817 3165.90879 -0.16937 3163.79974 3163.66994 -0.12980

B /MHz 1307.45486 1310.63692 3.18206 1307.66472 1310.87852 3.21379

C /MHz 925.72913 927.13048 1.40135 925.93898 927.46146 1.52247

CorrectedCalculated

ValuesExperimental Deviation

3163.63037 3163.66994 0.03957

1310.84678 1310.87852 0.03174

927.34034 927.46146 0.12112

•Anharmonic DFT calculation at the B97-1/cc-pVTZ//ANO-DZP level

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Molecules Quinazoline Quinoline [1,5]-naphthyridine

Modes GS ν38 GS ν45 ν41 GS ν22 ν18

Experimental -0.13619 -0.13406 -0.12940

Molecules Quinazoline Quinoline [1,5]-naphthyridine

Modes GS ν38 GS ν45 ν41 GS ν22 ν18

Experimental -0.13619 -0.44721 -0.13406 -0.64132 -0.36925 -0.12940 -0.68598 -0.46407

Molecules Quinazoline Quinoline [1,5]-naphthyridine

Modes GS ν38 GS ν45 ν41 GS ν22 ν18

Calculated -0.12239 -0.41006 -0.12504 -0.70649 -0.37344 -0.12718 -0.67650 -0.43612

Experimental -0.13619 -0.44721 -0.13406 -0.64132 -0.36925 -0.12940 -0.68598 -0.46407

Molecules Quinazoline Quinoline [1,5]-naphthyridine

Modes GS ν38 GS ν45 ν41 GS ν22 ν18

Calculated -0.12239 -0.41006 -0.12504 -0.70649 -0.37344 -0.12718 -0.67650 -0.43612

Experimental -0.13619 -0.44721 -0.13406 -0.64132 -0.36925 -0.12940 -0.68598 -0.46407

Deviation -0.0138 -0.0620 -0.0090 0.0651 0.0041 -0.0022 -0.0094 -0.0279

Inertial Defect

The inertial defect is defined for a molecule as:

• Check the reliability of our fitted rotational constants

• Contribution of the out of plane low frequency modes (GS)

• Correlation with the amplitude of the deformation motions (ES)

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Comparison Simulated/Experimental Spectrum

Quinoxaline

12

• Pure rotational transitions in the ES. Collaboration: LPCA Dunkerque (Fr) & PhLAM Laboratory (Fr) & IP PAS (Pl)

Conclusion & Perspectives

• Important database of rotational information in the IR Simulation at different resolution and at low temperature

• Study of larger molecules :

Jet-AILES Experiment(IPR, LADIR, PhLAM, SOLEIL) FluorenePhenanthrene

FA09 – Roger Adams Lab 116 – 11h01 to 11h16 AM