Institut für Physikalische Chemie & Elektrochemie, Lehrgebiet A.ppt Zentrum für Festkörperchemie & Neue Materialien Columbus 2010 MICROWAVE SPECTROSCOPY

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<Dateiname>.ppt

Zentrum für Festkörperchemie

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Materialien

Columbus 2010 Columbus 2010

MICROWAVE SPECTROSCOPY OF ALKALOIDS:

THE CONFORMATIONAL SHAPES OF NICOTINE

Jens-Uwe Grabow, Santiago Mata, Juan Carlos López,I. Pena, C. Cabezas, Susanna Blanco, Jóse Luis Alonso

Departamento de Química-Física y Química-InorgánicaUniversidad de Valladolid

Institut für Physikalische Chemie & Elektrochemie

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Columbus 2010 <Dateiname>.ppt


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Materialien

Rotational Spectra:Unambiguous Fingerprint

Sevoflurane

A. Lesarri, A. Vega-Toribio, R. D. Suenram, D. J. Brugh, J.-U. Grabow, Phys.Chem.Chem.Phys., in press(2010).

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Large Species/Multiple Conformers:Challenging Identification of

Fingerprints Enflurane

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Coaxial oriented Beam-Resonator Arrangement (COBRA):molecular excitation

tMW pulse

1μs

before excitation pulse: dipole moments cancel

single particle, Schrödinger equation:

iH

iH ,ensemble properties, von Neumann equation

wavefunction

density matrix

J.-U. Grabow, W. Stahl, Z. Naturforsch. 45a, 1043 (1990).

)()(

)()(

tt

tt

bbba

abaa

density matrix:

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molecular interaction with radiationshort stimulus Density Matrix formalism

00

01

0 baab (no) coherence:

thermal population: 0 bbaa

Eb

Ea

many two-level systems

21

2

221

i

i

0, baab coherence:

population equillibration: 0 bbaa

„π/2“ pulse

bbaaw

baabu )( baabiv

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Coaxial oriented Beam-Resonator Arrangement (COBRA):molecular response

E

t

T = 100μs

MW signal

after excitation pulse: oscillating macroscopic dipole moment

Fourier Transform

Frequency Domain, Spectrum

Time Domain, FID

U. Andresen, H. Dreizler, J.-U. Grabow, W. Stahl, Rev.Sci.Instrum. 61, 3694 (1990).

J.-U. Grabow, W. Stahl, H. Dreizler, Rev.Sci.Instrum. 67, 4072 (1996).

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<Dateiname>.ppt


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Columbus 2010

“coaxially oriented beam resonator arrangement“(COBRA) FTMW-Spectrometer

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COBRA FT-MW SpectrometerHannover

J.-U. Grabow, W. Stahl, H. Dreizler, Rev. Sci. Instr. 67 (1996) 4072.

FWHM: 3 kHzbandwidth: < 1 MHzrange: 2-26.5 GHz

10mW…200mW

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<Dateiname>.ppt


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Columbus 2010

molecular interaction with radiationfast passage Density Matrix formalism

00

01

0 baab (no) coherence:

thermal population: 0 bbaa

Eb

Ea

many two-level systems

21

2

221

i

i

0, baab coherence:

population equillibration: 0 bbaa

„π/2“ pulse

bbaaw

baabu )( baabiv

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IMPACT FT-MWValladolid

Inphase/Quadraturephase-Modulation-Passage Acquired-Coherence-Technique

1W…20W

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(IMPACT) FTMW - Spectrometer

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(IMPACT) FTMW - Spectrometer

Computer

Pulse Sequence Generation

Arbitrary Waveform Generation

Digitizer

HF electronics

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IMPACT FT-MW Spectrometerfirst-day spectral examples

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Nicotine:Two Conformations

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IMPACT FT-MW SpectrometerThe alkaloid nicotine

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Trans-a Trans-b Th Exp. Th Exp. A / MHz 2063,676 2059,56080 (70) 2048,750 2045,68593 (92)

B / MHz 580,305 579,870499 (173) 583,709 583,257787 (144)

C / MHz 550,970 549,322724 (203) 554,739 552,824539 (151)

-0.96106215 -0.96121897

Qua N1 Qua N5

aa / MHz 2,180927 2,1327 (165) 2,099717 2,0620 (178)

bb / MHz 2,661291 2,5793 (152) 2,604833 2,5666 (322)

cc / MHz -4,842218 -4,7119 (152) -4,704551 -4,6286 (322) Qua N8 Qua N21

aa / MHz -1,130406 -1,1672 (128) 0,912761 0,8753 (178)

bb / MHz 3,148936 3,3328 (131) 3,175922 3,1669 (319)

cc / MHz -2,018530 -2,1656 (131) -4,088683 -4,0423 (319)

a 2,266 -1,490

b -0,151 0,439

c -1,258 -2,635

total 2,596 3,059

E (h) -497,6200972 -497,6191493

ΔE zpe MP2 / cm-1 0 208,040002

Nicotine:Two Conformations

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IMPACT FT-MW Spectrometerfield focussing reflector / coaxial LASER ablation

LASER

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IMPACT FT-MW Spectrometer / LASER ablationamino acid proline: first results

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IMPACT FT-MW Spectrometer


targeted resolution: FWHM: ~3 kHzbandwidth: 1 GHz (x n)range: 2-26.5 GHz

1W…20W

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Columbus 2010

AcknowledgementAcknowledgement

Deutsche Forschungsgemeinschaft (DFG)

Land Niedersachsen

Ministerio de Ciencia e Innovacion

Junta de Castilla y Leon

Wolfgang Rogge

Feinmechanikwerkstatt Institut für Physikalische Chemie

Documents

Institut für Physikalische Chemie & Elektrochemie, Lehrgebiet A.ppt Zentrum für Festkörperchemie & Neue Materialien Columbus 2010 MICROWAVE SPECTROSCOPY