Two-Dimensional Chirped-Two-Dimensional Chirped-Pulse Fourier Transform Pulse Fourier Transform Microwave SpectroscopyMicrowave Spectroscopy

Amanda ShirarAmanda ShirarJune 22, 2010June 22, 2010

6565thth OSU International OSU International Symposium on Molecular Symposium on Molecular

SpectroscopySpectroscopy

Introduction: 2D Introduction: 2D SpectroscopySpectroscopy

Barbet-Massin, E. Barbet-Massin, E. et al.et al. J. Am. Chem. Soc. J. Am. Chem. Soc. 20102010, , 132132, 5556-5557., 5556-5557. Calhoun, T.; Calhoun, T.; et al.et al. J. Phys. Chem. B J. Phys. Chem. B 20092009, , 113113, , 16291-16295.16291-16295.

NMR IR Visible UV X-ray

Initial LimitationsInitial LimitationsPulse SequencesPulse Sequences - - Problem:Problem:

- t- t11 Resolution Resolution - Multiple Microwave - Multiple Microwave GeneratorsGenerators

- - Solution:Solution: Arbitrary Waveform Arbitrary Waveform GeneratorGenerator

- Pulse Shaping- Pulse Shaping- Sequence Mode- Sequence Mode

2D CP-FTMW Spectroscopy2D CP-FTMW Spectroscopy- Experimental Procedure- Experimental Procedure- Data Processing- Data Processing

Vogelsanger, Vogelsanger, et atl.et atl. Chem. Phys. Lett.. Chem. Phys. Lett.. 19881988, , 144144, 180-186., 180-186.

1-Chloro-1-Fluoroethylene1-Chloro-1-Fluoroethylene

CP-FTMW SpectrometerCP-FTMW Spectrometer

13 GHz PDRO

12 GHz Oscilloscop

e (40 Gs/s)

13 GHzFilter

200W

ArbitraryWaveformGenerator

100 MHz Quartz Oscillator

GHz Chirped Pulse0.1-5 GHz

8-18 GHz

Pulsed Nozzle

0.9-10.9 GHz

1)

2)

3)

Free InductiveDecay

18.9 GHz PDRO

10 GHz Bandwidth10 GHz Bandwidth100 ps t100 ps t11 Resolution Resolution

2D Autocorrelation 2D Autocorrelation SpectrumSpectrum

000000F=1.5F=1.5

111111

Energy Level SchemeEnergy Level SchemeF=1.5F=1.5

F=0.5F=0.5F=2.5F=2.5

1-Chloro-1-Fluoroethylene1-Chloro-1-Fluoroethylene(CFE)(CFE)

Time DomainTime Domain

pu

mp tt11

pro

be

(Scan)(Scan)

11 22 33 44tt

22

A B C

t1 (nsec)

2D Plots of CFE2D Plots of CFE

000000F=1.5F=1.5

111111

Energy Level SchemeEnergy Level SchemeF=1.5F=1.5

F=0.5F=0.5F=2.5F=2.5

A B C

A

B

C

CFE Assignments CFE Assignments According To:According To:

Leung, H.; Leung, H.; et al.et al. J. Mol. Spec. J. Mol. Spec. 20092009, , 253253, 116-121., 116-121.

2D Plots of CFE2D Plots of CFE CFE Assignments CFE Assignments According To:According To:

Leung, H.; Leung, H.; et al.et al. J. Mol. Spec. J. Mol. Spec. 20092009, , 253253, 116-121., 116-121.

000000F=1.5F=1.5

111111

Energy Level SchemeEnergy Level SchemeF=1.5F=1.5

F=0.5F=0.5F=2.5F=2.5

Difficulties of Broadband Difficulties of Broadband 2D2D

ProblemsProblems

Acquisition Time:Acquisition Time:

Resolution in tResolution in t11

Equipment:Equipment:Sampling at Nyquist Sampling at Nyquist

RateRate

Data Storage:Data Storage:Trillion Data pointsTrillion Data points

SolutionSolution

Set Sampling Rate in Set Sampling Rate in tt11

1 ns Step Size:1 ns Step Size:500 MHz Bandwidth500 MHz Bandwidth

0.5 ns Step Size:0.5 ns Step Size:1 GHz Bandwidth1 GHz Bandwidth

1D Slices1D Slices

Data ProcessingData Processing

Frequency AliasingFrequency Aliasing14.120 GHz 14.120 GHz 120 MHz 120 MHz14.128 GHz 14.128 GHz 128 MHz 128 MHz14.137 GHz 14.137 GHz 137 MHz 137 MHz

A B C

A B

CA

B

C

Data ProcessingData Processing

PredictedExperimental

Use the Density Use the Density Matrix to predict Matrix to predict

the 1D slicesthe 1D slicesTC09: David TC09: David

WilcoxWilcox

Further ResearchFurther Research

Kelly Hotopp TC12Kelly Hotopp TC12: Applications of 2D : Applications of 2D CP-FTMW Spectroscopy CP-FTMW Spectroscopy

Non-Selective ExcitationNon-Selective Excitation

Coherence TransferCoherence Transfer

AcknowledgementsAcknowledgements

• Kelly HotoppKelly Hotopp• David WilcoxDavid Wilcox• Brian DianBrian Dian

• Dr. Henry & Dr. Henry & Camille Dreyfus Camille Dreyfus Foundation - Foundation - Young Faculty Young Faculty ScholarScholar

BlankBlank

2-D Time Resolved Techniques2-D Time Resolved Techniques - Selective Excitation- Selective Excitation

- Pump single conformation- Pump single conformation - Probe all-conformations- Probe all-conformations

- Relatively simple interpretation - Relatively simple interpretation of of time domain spectrum time domain spectrum

- Non-Selective Excitation- Non-Selective Excitation- Pump all conformers- Pump all conformers- Probe all conformers- Probe all conformers

AliasingAliasing

Ultra-Broadband scan Ultra-Broadband scan ~~ 2 months 2 months

500 MHz (2048 steps) 500 MHz (2048 steps) ~~ 3.5 hours 3.5 hours

1 GHz (4096 steps) 1 GHz (4096 steps) ~~ 7 hours 7 hours

Introduction: 2D NMRIntroduction: 2D NMR

-2--2-MicroglobulinMicroglobulin

Benn & Günther, Benn & Günther, Ang. Chem. Int. Ed. Engl. Ang. Chem. Int. Ed. Engl. 19831983, , 2222, 5350-380., 5350-380.

Toluene Toluene DerivativesDerivatives

Introduction: Further 2DIntroduction: Further 2D

Shim & Zanni, Shim & Zanni, Chem. Phys. Phys. Chem. Chem. Phys. Phys. Chem. 20092009, , 1111, 748-761., 748-761.

Light HarvestingLight HarvestingComplex IIComplex II

Amyloid FiberAmyloid FiberFormationFormation

2D Rotational 2D Rotational SpectroscopySpectroscopy

J=2J=2

J=1J=1

J=3J=3

Frequency DomainFrequency Domain

MW Pump MW Pump (Single Trans.)(Single Trans.)

MW Probe MW Probe (Broadband)(Broadband)

Benn & Günther, Benn & Günther, Ang. Chem. Int. Ed. Engl.. Ang. Chem. Int. Ed. Engl.. 19831983, , 2222, 5350-380., 5350-380.