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EXTENDING ROTATIONAL SPECTROSCOPY TO HIGHLY EXCITED VIBRATIONAL STATES
UofR EXTENDING ROTATIONAL SPECTROSCOPY TO HIGHLY EXCITED VIBRATIONAL STATES John Muenter, Dept. of Chemistry, Univ. of Rochester with many collaborators from Rochester and the EPFL, Lausanne, Switzerland 61st Molecular Spectroscopy Symposium Paper TH10; 6/20/2006
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Rochester NEW TECHNIQUES & CHALLENGES FOR ROTATIONAL SPECTROSCOPY
FREQUENCY RANGE RESOLUTION SENSITIVITY MOLECULAR SPECIES DYNAMIC SPECTROSCOPY He NANODROPLETS EXCITED STATES EXCITED VIBRATIONAL STATES ON GROUND ELECTRRONIC SURFACES
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III. DETECTION III. DETECTION A. A. IR Absorption IR Absorption B. B. Mass Spec. ( Mass Spec. ( MBER MBER ) ) C. C. LIF Detection of Parent Species LIF Detection of Parent Species D. D. Unimolecular Dissociation- Unimolecular Dissociation- LIF Detection of Product LIF Detection of Product E. E. Vibrational Mediated Vibrational Mediated Photodissoc Photodissoc .- .- LIF Detection of Product LIF Detection of Product F. F. Spontaneous Emission of Product Spontaneous Emission of Product E. REMPI
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HCCD NH3 n1 = 1 J=3, K=3
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III. DETECTION III. DETECTION III. DETECTION III. DETECTION A. A. A. A. IR Absorption IR Absorption IR Absorption IR Absorption B. B. B. B. Mass Spec. ( Mass Spec. ( Mass Spec. ( Mass Spec. ( MBER MBER MBER MBER ) ) ) ) C. C. C. C. LIF Detection of Parent Species LIF Detection of Parent Species LIF Detection of Parent Species LIF Detection of Parent Species D. D. D. D. Unimolecular Dissociation- Unimolecular Dissociation- Unimolecular Dissociation- Unimolecular Dissociation- LIF Detection of Product LIF Detection of Product LIF Detection of Product LIF Detection of Product E. E. E. E. Vibrational Mediated Vibrational Mediated Vibrational Mediated Vibrational Mediated Photodissoc Photodissoc Photodissoc Photodissoc .- .- .- .- LIF Detection of Product LIF Detection of Product LIF Detection of Product LIF Detection of Product F. F. F. F. Spontaneous Emission of Product Spontaneous Emission of Product Spontaneous Emission of Product Spontaneous Emission of Product E. E. E. E. REMPI REMPI REMPI REMPI
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HF, HCN, H2O, HCCCl, HCCBr
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III. DETECTION III. DETECTION III. DETECTION III. DETECTION A. A. A. A. IR Absorption IR Absorption IR Absorption IR Absorption B. B. B. B. Mass Spec. ( Mass Spec. ( Mass Spec. ( Mass Spec. ( MBER MBER MBER MBER ) ) ) ) C. C. C. C. LIF Detection of Parent Species LIF Detection of Parent Species LIF Detection of Parent Species LIF Detection of Parent Species D. D. D. D. Unimolecular Dissociation- Unimolecular Dissociation- Unimolecular Dissociation- Unimolecular Dissociation- LIF Detection of Product LIF Detection of Product LIF Detection of Product LIF Detection of Product E. E. E. E. Vibrational Mediated Vibrational Mediated Vibrational Mediated Vibrational Mediated Photodissoc Photodissoc Photodissoc Photodissoc .- .- .- .- LIF Detection of Product LIF Detection of Product LIF Detection of Product LIF Detection of Product F. F. F. F. Spontaneous Emission of Product Spontaneous Emission of Product Spontaneous Emission of Product Spontaneous Emission of Product E. E. E. E. REMPI REMPI REMPI REMPI
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Optical Layout etalon PD OG lamp Water vapor 0.10 mbar
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H2CO
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III. DETECTION III. DETECTION A. A. IR Absorption IR Absorption B. B. Mass Spec. ( Mass Spec. ( MBER MBER ) ) C. C. LIF Detection of Parent Species LIF Detection of Parent Species D. D. Unimolecular Dissociation- Unimolecular Dissociation- LIF Detection of Product LIF Detection of Product E. E. Vibrational Mediated Vibrational Mediated Photodissoc Photodissoc .- .- LIF Detection of Product LIF Detection of Product F. F. Spontaneous Emission of Product Spontaneous Emission of Product E. REMPI
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HOCl
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III. DETECTION III. DETECTION A. A. IR Absorption IR Absorption B. B. Mass Spec. ( Mass Spec. ( MBER MBER ) ) C. C. LIF Detection of Parent Species LIF Detection of Parent Species D. D. Unimolecular Dissociation- Unimolecular Dissociation- LIF Detection of Product LIF Detection of Product E. E. Vibrational Mediated Vibrational Mediated Photodissoc Photodissoc .- .- LIF Detection of Product LIF Detection of Product F. F. Spontaneous Emission of Product Spontaneous Emission of Product E. REMPI
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Water: vibrationally mediated photodissociation
OH( A ~ 2 S + ) ~ LIF A 1 B 1 ~ OH( X 2 P ) + H v OH = 4,0- v=0 ~ H2O (X A ) 1 1
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The quantum beat approach:
Coherently detect excited molecules t P(t, E, ) J,K M Wait… Coherently prepare excited molecules
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|4,0->; |5,0->; |4,0->|2>; |8,0+>
Water OH( A ~ 2 S + ) ~ A 1 B LIF 1 ~ OH( X 2 P ) + H v OH = 4,0- ma & mb for H2O & HDO in |4,0->; |5,0->; |4,0->|2>; |8,0+> v=0 ~ H2O (X A ) 1 1
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Energy Level Diagram Double Resonance
1. Gain in excitation efficiency: 0.5 * 0.5 = vs n (double resonance) (direct transition) 2. Rotational pre-selection => simple assignment
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Results for vOH=9: 111 211 Rotational selection rules: DJ = 0, ±1,
Dka = 0, Dkc = ±1 = 211
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More results for vOH=9…
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Results for vOH=10: x 50 More lines… S/N >3000
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ACKNOWLEDGEMENTS TOO MANY TO THANK INDIVIDUALLY BUT THANKS TO ALL!
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