IDENTIFYING FLUORESCENT

HYDROCARBON RADICALS FROM A BENZENE

DISCHARGE.

Neil J. Reilly, Damian L. Kokkin, Scott H. Kable & Timothy W. Schmidt

(Not)

Diffuse interstellar bands…

http://bjm.scs.uiuc.edu/research/opb2.php

What is this molecule?

Benzene discharge (2d)9998

9997

1010

1011

2121

2120

2122

Rotational branch trails

C3

C2

Benzene discharge

460 480 500 520 540 560 580472

473

474

475

476

477

0200.0400.0600.0800.0100012001400160018002000220024002600280030003200340036003800400042004400460048005000

Emission wavelength (nm)

Exc

itatio

n w

ave

len

gth

(n

m)

?

460 480 500475

476

477

080.00160.0240.0320.0400.0480.0560.0640.0720.0800.0880.0960.01040112012001280136014401520160016801760184019202000

Emission wavelength (nm)

Exc

itatio

n w

avel

eng

th (

nm

)

Benzene discharge

473 474 475 476 477 478 479

456

458

460

462

464

466

468

470

472

474

040.0080.00120.0160.0200.0240.0280.0320.0360.0400.0440.0480.0520.0560.0600.0640.0680.0720.0760.0800.0840.0880.0920.0960.01000

X Axis Title

Y A

xis

Titl

eBenzene discharge

Emission wavelength (nm)

Exc

itatio

n w

avel

engt

h (n

m)

Benzene discharge

Claude Monet. Water-Lilies. 1914. Oil on canvas. National Museum of Western Art, Tokyo, Japan.

Benzene discharge

C3?

?

??

?

Benzene discharge

C2

?

? ?

?

??

?

?

Benzene discharge

origin DF

C2C2

Benzene discharge

C2

?

? ?

?

??

?

?

? = same molecule!

C6H6 discharge

Our origin band

DIB

Benzene discharge

C2

Benzene discharge

C2

Benzene discharge

C6H6

C6H5D

C6D6

Benzene discharge

C6H6

C6H5D

C6D6

Benzene discharge

C6H6

C6H5D

C6D6

CnH6?

Benzene discharge

Benzene discharge

•Coincidence? Both spectra generated from C6H6 discharge•Both coincident with broad DIBs•What could be the broadening mechanism? Inefficient radiative cooling?•We’ll try to get a R2C2PI spectrum later this year…

I’ll tell you what it is next year