fluorescence spectroscopy of jet- cooled phenylvinylacetylene in its ground and first excited states...

Fluorescence spectroscopy of jet-cFluorescence spectroscopy of jet-cooled phenylvinylacetylene in its ooled phenylvinylacetylene in its ground and first excited statesground and first excited states

Speaker: Ching-Ping LiuCoworkers: Josh Newby and Christian Müller

Advisor: Dr. Timothy ZwierDepartment of Chemistry, Purdue University

Motivation(1)Completing a series:

(2) Structural isomerization:

(3) C10H8 isomers: Alternatives to naphthalene in combustion, planetary atmospheres?

Previous detection: C4H2* + styrene, no spectral analysis

1-phenyl-1,3-butadiene

Sharp UV spectrum

phenylvinylacetylene phenyldiacetylene

Broad UV spectrum

Z-formE-form

Experiment

Laser beam

Collection mirrors

Collimating lens

To optics Housing

Supersonic expansion

Fluorescence excitation Dispersed fluorescence

PMT Monochromator / CCD

0 200 400 600 800 1000 1200 1400

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Arb

itra

ry U

nit.

Relative wavenumber / cm-1

Fluorescence excitation spectrum of PVA

150 200 250 300 350 400 450

0 200 400 600 800 1000 1200 1400 1600

0.0

0.2

0.4

0.6

0.8

1.0

Arb

itra

ry U

nit.

Relative wavenumber / cm-1

Single vibrational level dispersed fluorescence spectrum with the excitation of the origin band.

0248

01

01 4847

0132

0131

0128

0126

0125

0119

0130

02

01 4828 0

201 4826

02

01 4825

0123

0118

000

0448

Torsional progression

Cs symmetrya (in plane) modes: 1-33

a (out of plane) modes: 34-48

48Obs / cm-1

89

186

02480448

1

23

4

5

6

150 200 250 300 350 400 450

0 200 400 600 800 1000 1200 1400 1600

Arb

itrar

y U

nit.

Arb

itrar

y U

nit.

Arb

itrar

y U

nit.

Relative wavenumber / cm-1

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

266

222

254

326 334

400

Excite 222 cm-1

Excite 254 cm-1

Excite 266 cm-1

Excite 326 cm-1

Excite 334 cm-1

Excite 400 cm-1

Part of the FE spectra

SVLF spectra

1032

1132

1031

1131

FE spectra with various backing pressure of the carrier gases. (a) He 15 psi, and (b) He 40 psi, and (c) He 80 psi.

0 40 80 120 160 200 240

Relative wavenumber / cm-1

Arb

itrar

y U

nit.

(a)

(b)

(c)

Clusters

Cold band

Hot bands

v=0v=1

v=0v=1

v=2v=3

S1

S0

-2124

84158

232

104131

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

Arb

itra

ry U

nit.

- 21 cm-10

00

+ 24 cm-1000

+ 84 cm-1000

+ 158 cm-1000

+ 232 cm-1000

Single vibrational level dispersed fluorescence spectra of hot bands.

01

104847

1147

01

104846

1146

1144

1145

01

104847

1147

01

104845

01

104844

From v47=1

From v48=1

01

104645

01

104746

Duschinsky mixing

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

Arb

itra

ry U

nit.

+ 191 cm-1000

10

104746

12

104746

11

114746

+ 254 cm-1000

2246

2046

01

214846

+ 266 cm-1000

10

104745

11

1147451

101

10 474645

+ 400 cm-1000

2045

02

204645

2245

01

214645

SVLF spectra with excitation involving the out-of-plane modes.

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

Arb

itra

ry U

nit.

+ 104 cm-1000

1033

+ 222 cm-1000

+ 334 cm-1000

+ 539 cm-1000

1032

1132

1031

1131

1133

1028

1128

SVLF spectra with excitation involving the in-plane modes.

Arb

itrar

y U

nit.

Arb

itrar

y U

nit.

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumver / cm-1

+ 931 cm-1

+ 948 cm-1

+ 1214 cm-1

+ 788 cm-1

+ 810 cm-1

+ 815 cm-1 + 1279 cm-1

+ 726 cm-1000

000

000

000

000

000

000

000

Single vibrational level dispersed fluorescence spectra.

0 200 400 600 800 1000 1200 1400

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Arb

itra

ry U

nit.

Relative wavenumber / cm-1

Fluorescence excitation spectrum of phenylvinlyacetylene

10

104746

2046 1

0104645

1032

1031

2045 1

030

1028

1026

1025

1019

000

2047

10

104745

1023

0 50 100 150 200

1147

01

104847

01

104846

01

104845

1033

2047

10

104746

Warm condition

01

104844

Hot bands

0 200 400 600 800 1000 1200 1400 1600 1800

Arb

itra

ry U

nit.

Relative wavenumber / cm-1

240 250 260 270 280

1C-R2PI and hole-burning spectraConformer or isomer A

Conformer or isomer B

Ho

le-b

urn

Ho

le-b

urn

Pro

be

Pro

be

S0

S1

S0

S1R2PI

UVHB

0 200 400 600 800 1000 1200 1400 1600

Relative wavenumber / cm-1

Arb

itra

ry U

nit.

+ 260 cm-1000

band000

)(6b01

)(101

)(1201

89

186

34

74 ?

The SVLF spectrum with the excitation in the unknown band.

Benzene-type modes

Conclusion• The analysis and assignments of the ground and first excit

ed states of phenylvinylacetylene are reported. The spectroscopy reveals Duschinsky mixing with four lower-frequency out-of-plane modes and IVR at high excess energy.

• The unknown band at 260 cm-1 above the origin in FE spectrum is probably originated from the Z isomer.

Future work

1. Quantitatively analyze Duschinsky mixing with four low-frequency out-of-plane modes.

2. Synthesize the Z isomer to get the spectral information for comparison with the E isomer.

3. UV-induced structural isomerization of E- or Z-PVA.

Acknowledgement• Advisor: Dr. Timothy Zwier• Group members: Dr. Christian Müller* Dr. Jasper Clarkson Esteban Baquero Alvin Shubert Nathan Pillsbury Tracy LeGreve Josh Newby* Chirantha Rodrigo Josh Sebree

• Dr. Daniel Lee

Funding: Taiwan Merit scholarship