JET-COOLED LASER SPECTROSCOPY OF A JAHN-TELLER AND PSEUDO JAHN-TELLER ACTIVE

MOLECULE: THE NITRATE RADICAL (NO3)

1Laser Spectroscopy FacilityDepartment of ChemistryThe Ohio State University

6/23/2009

64th OSU International Symposium on Molecular Spectroscopy

2Arthor Amos Noyes Laboratory of Chemical Physics

California Institute of Technology

MING-WEI CHEN1, KANA TAKEMATSU2, MICHIO OKUMURA2 and TERRY A. MILLER1

Outline

Introduction Motivation and aims

Spectroscopy Geometry and vibronic coupling Spectroscopic review

Experiment Apparatus of NO3 measurement Initial results of NO3

Future works

Introduction Motivation and aims

Spectroscopy Geometry and vibronic coupling Spectroscopic review

Experiment Apparatus of NO3 measurement Initial results of NO3

Future works

NO3 in Atmosphere

NO3

NO2

N2O5

-NO2

-NO2, hν

+NO2hν-OO3

HNO3

hydrometeors

In troposphere

R. P. Wayne et al., Atmos. Envir. 25A, 1 (1991).

Nitrate radical (NO3) is an important radical intermediate in the night-time atmosphere, involved in the chemical transformations in both the stratosphere and the troposphere.

J.A. Logan, J. Geophys. Res. 86, 7210 (1983).

Mix

ing

Rat

io

10-10

10-11

10-12

10-13

10-14

hν

NO

-O

RO2

RO

NO NO2

RO2

TF08TF09TJ08RD05

RO

WJ10

Reactions of Radicals

RO2

OH

R’CHO

RO

RH

RO2NO2

RONO2

HO2

CO

CO2

R’C(O)O2

PAN

ROOH

O2

NO2HO2

NONO

hn

OH NO2

NO NO2

hn

OH

O2

O2

NO2

NO

DIsomerisation

Multistep

hn

NO2

O2

RO2

RO

NO3 NO2

RO2

RO

NO3

Day time

Night time

ONONO

NORONOROh

2

22

2332

2232

ONOONO

ONORONORO

R. P. Wayne et al., Atmos. Envir. 25A, 1 (1991).

Lightfoot et. al. Atmos. Envir. 26A, 1805 (1992). hν

O3

Motivations and Aims

The three energetically lowest states are coupled by vibronic interaction, and therefore a model molecule for understanding the coupling between nearby potential energy surfaces and the Jahn-Teller (JT)/pseudo Jahn-Teller (PJT) effects

Comprehensive understand of the molecular structure with LIF/SEP experiment and benchmark for ab initio calculations of NO3

M. Okumura J. F. Stanton, A. Deev and J. Sommar, Phys. Scr., 73, C64 (2006).

Vibronic Coupling (Linear)

aQ

U

bQ

aQ

U

bQ

Linear JT Pseudo JT

2/1221

21

2202

1 baba QkQkQQkU 2/122

122

02

1baba QQkQQkU

aQ

U

bQ

aQ

U

bQ

''~2EA

or

'~2EB

'~

22AX

''~2EA or '

~2EB

Quadratic JT/PJT Coupling

N

O

O O

D3h

C2v

.

.

.

.

.

.

Spectroscopy of Nitrate Radicals

NO3─

NO3 + e─

.

.

.

'~

22AX

"~2EA

'~2EB

MIR NIR

LEDF

PDSLIF

Absorption

Vis

NO3 + e─

• T. Ishiwata, I. Tanaka, K. Kawaguchi, and E. Hirota, J. Chem. Phys., 82, 2196 (1985).

• R. R. Fredl and S. P. Sander, J. Phys. Chem., 91, 2721 (1987).• E. Hirota, K. Kawaguchi, T. Ishiwata, and I. Tanaka, J. Chem. Phys., 95, 771 (1991).• K. Kawaguchi, T. Ishiwata, I. Tanaka, and E. Hirota, Chem. Phys. Lett., 180, 436

(1991).• T. Ishiwata, I. Tanaka, K. Kawaguchi, and E. Hirota, J. Mol. Spec., 183, 167 (1992).

• E. Hirota, T. Ishiwata, K. Kawaguchi, M. Fujitake, N. Ohashi, and I. Tanaka, J. Chem. Phys., 107, 2829 (1997).

• K. Kawaguchi, T. Ishiwata, E. Hirota, and I Tanaka, Chem. Phys., 231, 193 (1998).• A. Deev, J. Sommar, and M. Okumura, J. Chem. Phys., 122, 224305/1 (2005).• M. Jacox and W. E. Thompson, 64th International Symposium on Molecular

Spectroscopy, TF12 (2009).

• D. A. Ramsay, Proc. Colloq. Spectrosc. Int., 10, 583 (1962).• W. J. Marinelli, D. M. Swanson, and H. S. Johnston, J. Chem. Phys., 76, 2864

(1982).• M. Jacox and W. E. Thompson, 64th International Symposium on Molecular

Spectroscopy, TF12 (2009).

• T. Ishiwata, I. Fujiwara, Y. Naruge, K. Obl, and I. Tanaka, J. Chem. Phys., 87, 1349 (1983).

• B. Kim, P. L. Hunter, and H. S. Johnston, J. Chem. Phys., 96, 4057 (1992).• R. T. Carter, K. F. Schmidt, H. Bitto, and J. R. Huber, Chem. Phys. Lett., 257, 297

(1996).• L. Valachovic C. Riehn, K. Mikhaylichenko and C. Wittig, Chem. Phys. Lett., 258,

644 (1996).

• A. Weaver, D. W. Arnold, S. E. Bradforth, and D. M. Neumark, J. Chem. Phys., 94, 170 (1991).

Vibronic Selection Rules

22X A

2B E

2A E

Pump

DumpT0(cm-1)

15089

7064

0

ΔE = 8025 cm-1

Electronic States and Transitions

(Forbidden)

CH3O LIF/SEP Spectra

32892 32894 32896 32898 32900 32902 32904-25

-20

-15

-10

-5

0

5

32894.0 32894.1

-8

-6

-4

-2

0

2

P2b

pumped, moderate-resolution dump

P2a

pumped, moderate-resolution dump

32892 32894 32896 32898 32900 32902 32904-25

-20

-15

-10

-5

0

5

Dep

letio

n R

ate

(%)

32898.6 32898.7 32898.8

Dump Frequency / cm -1

32901.5 32901.6

P2a

+P2b

pumped, high-resolution dump

~2

3/2EX

~2

1AA

~2

1/2EX

LIF

SEP

32950 32955 32960 32965 32970 32975 32980

wavenumbers / cm-1

P2

J. Liu, M.-W. Chen, D. Melnik, J. T. Yi and T. A. Miller, J. Chem. Phys., 130, 074302 (2009)

pulse

continuous

Jet

Excitation laser beam

Schematic Diagram of LIF Detection

N2O5 with He/Ne mixture

3252 NONOON

Dump laser beam

Heated nozzle tip

LIF of NO3 Origin Band

L. Valachovic C. Riehn, K. Mikhaylichenko and C. Wittig, Chem. Phys. Lett., 258, 644 (1996).

15000 15050 15100 15150 15200 15250 15300

wavenumbers / cm-1

NO3 LIF spectrum, continuous flow.

Moderate-res.a

LIF of NO3 Origin Band

15100 15110 15120 15130 15140

wavenumbers / cm-1

FWHM ~ 0.19(7) cm-1

cw jet, scan step: 0.23 cm-1

pulse jet, scan step: 0.05 cm-1

bR. T. Carter K. F. Schmidt, H. Bitto and J. R. Huber, Chem. Phys. Lett., 257, 297 (1996).

High-res.b

aL. Valachovic C. Riehn, K. Mikhaylichenko and C. Wittig, Chem. Phys. Lett., 258, 644 (1996).

Summary and Future Works

Summary: Apparatus with both high-resolution

(FWHM~250MHz) and high-accuracy (σ~50MHz) for LIF and SEP measurements.

Preliminary NO3 LIF of origin band has been obtained.

Future works: Optimize the system to improve the

quality of the LIF spectrum. Measure the SEP spectra of and

transitions.

Summary: Apparatus with both high-resolution

(FWHM~250MHz) and high-accuracy (σ~50MHz) for LIF and SEP measurements.

Preliminary NO3 LIF of origin band has been obtained.

Future works: Optimize the system to improve the

quality of the LIF spectrum. Measure the SEP spectra of and

transitions.

XB~~

AB~~

XB~~

XB~~

.

.

.

'~

22AX

"~2EA

'~2EB

HR-LIF

HR-SEP

.

.

.

.

.

.

S. Kasahara, K. Kanazawa, Y. Semba, K. Yoshida, M Baba, T. Ishiwata and E. Hirota, 64th International Symposium on Molecular Spectroscopy, TJ07 (2009).

Acknowledgement

The Miller Group (OSU):

Dr. Miller

Dmitry Melnik (WJ10, RD05)

Phillip Thomas (TJ08)

Gabriel Just (TF08, TF09)

Rabi Chhantyal-Pun

Terrance Codd

Neal Klein Funding: NSFYour attention!

The Okumura Group (CIT):

Dr. Okumura

Kana Takematsu (WJ11, RD02)