Rotationally-resolved high-resolution laser spectroscopy of the B 2 E’ – X 2 A 2 ’ transition...

Rotationally-resolved high-resolution laser spectroscopyof the B 2E’ – X 2A2’ transition of 14NO3 radical

69th International Symposium on Molecular Spectroscopy@ Champaign-Urbana, Illinois, The United States

2014 / June / 16th

MI13

Shunji Kasahara1, Kohei Tada1†, Takashi Ishiwata2, and Eizi Hirota3

1 Kobe University, Japan;2 Hiroshima City University, Japan;

3 The Graduate University for Advanced Studies, Japan;† Research Fellow of Japan Society for the Promotion of Science.

　 Introduction

D3h

2NO2

HNO3 + R etc.

NO2 　 + O

NO 　 + O2

+ NO+ RH

NO3

+ hν

+ hν

Wavenumber / 1000 cm-1

20

15

10

5

0

NO2 + O 　　　　 NO3 NO + O2

O2 (b 1Σg+)

O2 (a 1Δg)

O2 (X 3Σg-)

B 2E’

A 2E’’

X 2A2’

Vibronic Band~ 16000 cm-1 (~ 625 nm)

0-0 band ~ 15100 cm-1 (~ 662 nm)

B - X 遷移

K. Mikhaylichenko et al., J. Chem. Phys., 105, 6807 (1996)

reaction coordinate

NO2 + O3 → NO3 + O2

N2O5 ⇄ NO3 + NO2

B 2E’ ： … (4e’)3 (1e’’)4 (1a2)2 ~ 15000 cm-1

A 2E’’ ： … (4e’)4 (1e’’)3 (1a2)2 ~ 7000 cm-1

X 2A2’ ： … (4e’)4 (1e’’)4 (1a2)1 0 cm-1

662 nmAbsorption spectrum of 14NO3 (Visible)

J. Chem. Soc. Faraday 1176, 785 (1980).

⑤ LIF and Absorption spectra of 14NO3 B-X transition

Absorption spectrum of 14NO3 (Visible)

J. Chem. Soc. Faraday 1176, 785 (1980).

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

N2O5 → NO3 + NO2

M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)

Resolution ： 0.2 cm-1

14NO3 B 2E’-X 2A2’ transition

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

LIF spectra of 14NO3 and 14NO2

N2O5 → NO3 + NO2

R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)

Vibronic band0 - 0 band


NO2


INTENSITY×5

?

14NO2 A 2B2-X 2A1 transition (Imax at 16849.8 cm-1)


14NO3 B 2E’-X 2A2’ transition

D

　 Exprimental setup

Absolute wavenumber mesurement system (Accuracy : 0.0001 cm-1)

Etalon

Liq.N2

Pump Pump

Pulsed Nozzle

Skimmer(ϕ= 2 mm)

Filter

N2O5 → NO3 + NO2 Slit(2 mm)

PBS

Molecular Beam (Typical linewidth : 0.0007 cm-1)

N2O5 + ArComputer

532 nm around 660 or 625 nm

Single mode laser ( Γ = 0.00003 cm-1 )PD

BS : Beam splitterPBS : Polarization beam splitterEOM : Electro-optic modulatorPD : Photo diodePMT : Photomultiplier tube

BS

EOM

I2 Cell

Heater 300 ℃NO2 + He

Ring DyeLaser

Nd:YVO4

Laser

Mirror Heater off

Photon Counter

PMT

~ 150 strong (> 15% of max) lines and more than 3000 weak (< 15% of max) lines were observed. ← too many!

The rotational assignment was very difficult.

(1) Combination difference

→ 0.0248 cm-1 line pairs

(2) Zeeman effect

→ Unambiguous Assignment

　 High-resolution LIF spectrum 14NO3 B-X 0-0 band at 662 nm

0.1 cm-1

15100.15 15100.20 15100.25

Wavenumber / cm-1

0.0248 cm-1

σ-pump (H⊥E) ΔMJ = ±1 π-pump (H // E) ΔMJ = 0

15100.20 15100.25

0 G

42 G

71 G

102 G

125 G

163 G

188 G

223 G

245 G

280 G

303 G

335 G

360 G

Wavenumber / cm-1

15100.20 15100.25

0 G

42 G

71 G

102 G

125 G

163 G

188 G

223 G

245 G

280 G

303 G

335 G

360 G

Wavenumber / cm-1

0.0246 cm-1 0.0246 cm-1

　 Zeeman effect around 15100.2 cm-1

40 G

70 G

100 G

160 G

190 G

220 G

305 G

40 G

70 G

100 G

160 G

190 G

220 G

305 G

σ-pump: ΔMJ = ±1

π-pump: ΔMJ = 0

(σ:4+6/π:2+3) pair

Symmetry-adopted basis setsThe X 2A2’ state:

The B 2E’ state:

JJ

J

MkJSN

kNMkJS

N

kN

FMNJSkN

,,,22

1,,,

22

1

,,,,,

21

21

21

21

21

21

121

21

JJ

J

MkJSN

kNMkJS

N

kN

FMNJSkN

,,,2

,,,2

,,,,,

21

21

21

21

21

21

221

21

JPJ

J

J

MPJSMPJS

EMSPJ

,,,1)(,,,12

1

',,,,,

21

21

21

21

2/32

21

JPJ

J

J

MPJSMPJS

EMSPJ

,,,1)(,,,12

1

',,,,,

21

211

21

21

2/12

21

Hund’s case (b) basis

Hund’s case (a) basis

The X 2A2’ state: HZ = gS μB H·S

The B 2E’ state: HZ = gS μB H·S + gL μB H·Leff

)12)(1(1

')()12)(1'2(

1

'

')(

0

1

'

')(''''

'''

'''''

SSSS

q

SgdgJJ

P

J

qP

J

M

J

M

JHJPMHMPJ

SSPPeL

PJ

JJq

MJMMBJZJ

J

JJ

ζ

JJ

JNSMJKKNNMMBSJZJ

M

J

M

JN

S

J

J

SSSSJJ

HgNKSJMHMJSKN J

JJ

0

1

'

'

1

')12)(1()12)(1'2(

)(''''' 1'''''

Refs: Endo et al., J. Chem. Phys., 81, 122 (1984)

Hirota, High-Resolution Spectroscopy of Transient Molecules, Springer (1985)

μB (= 4.6686×10-5 cm-1 G-1): Bohr magneton, gS: the electron spin g factor,

gL: the electron orbital g factor, and ζed: the effective value of <Λ|Lz|Λ>.

Zeeman Hamiltonians and matrix elements

0 100 200 300 400

15100.18

15100.20

15100.22

15100.24

Transition Energy / cm-1

Magnetic Field / Gauss

R(+0.5)

P(+0.5)

R(-1.5)RR

(-0.5)(+0.5)

P (-0.5)P(+0.5)

P(+1.5)

R(-0.5)

P(-0.5)

(σ:4+6/π:2+3) pair Zeeman splitting: transition to (2E’3/2, J = 1.5)

J = 1.5 ← 1.5

J = 1.5 ← 0.5

At 300 G

+ 0.5+ 1.5

– 0.5– 1.5

– 0.5+ 0.5

+ 1.5

+ 0.5– 0.5– 1.5

MJ

σ-pumpΔMJ = ±1

gS = 2.0215(4)

gS = 2.103(6)gLζed = – 0.138(11)

0 200 400 600

0.88

0.90

0.92

0.94

0.96

+ 0.5– 0.5

+ 1.5

+ 0.5– 0.5– 1.5

+ 1.5

+ 0.5– 0.5– 1.5

MJ

Magnetic field / G

Term energy / cm-1

J’ = 1.5

J” = 0.5

J” = 1.5

0 200 400 60015101.10

15101.12

15101.14

15101.16

15101.18

15101.20

0 100 200 300 400

15100.18

15100.20

15100.22

15100.24



R(+0.5)

P(+0.5)

R(-1.5)RR

(-0.5)(+0.5)

P (-0.5)P(+0.5)

P(+1.5)

R(-0.5)

P(-0.5)

0 100 200 300 400

15100.18

15100.20

15100.22

15100.24



R(+0.5)

P (+0.5)

R(-1.5)RR

(-0.5)(+0.5)

P (-0.5)P (+0.5)

P (+1.5)

R(-0.5)

P (-0.5)

ΔMJ (MJ”)

1510

0.20

1510

0.250 G

42 G

71 G

102

G

125

G

163

G

188

G

223

G

245

G

280

G

303

G

335

G

360

G

Wav

enum

ber

/ cm

-1

σ-pump (H⊥E) ΔMJ = ±1 π-pump (H // E) 　

　 ΔMJ = 0

　 Zeeman effect around 15130.75 cm-1

15130.75 15130.80

0 G

71 G

125 G

Wavenumber / cm-1

188 G

245 G

303 G

360 G

70 G

360 G

0.0246 cm-1

15130.75 15130.80

0 G

71 G

125 G

Wavenumber / cm-1

188 G

245 G

303 G

360 G

70 G

305 G

190 G

0.0246 cm-1

σ-pump: ΔMJ = ±1

π-pump: ΔMJ = 0

(σ:2+3/π:1+2) pair

σ-pump (H⊥E)ΔMJ=±1

Energy / cm-1

J’’=1.5

J’’=0.5

J’=0.5

MJ

+ 0.5

‐0.5

+ 0.5

‐0.5

+ 0.5

‐0.5

+ 1.5

‐1.5

Magnetic field / Gauss0 100 200 300 400

0.88

0.9

0.92

0.94

15131.66

15131.68

15131.7B 2E’1/2

X 2A2’(K’’=0 ， N’’=1)

0 100 200 300 40015130.72

15130.74

15130.76

15130.78

15130.8σ-pump (H⊥E)

Wav

enu

mb

er /

cm-1

15130.7

15130.72

15130.74

15130.76

15130.78

15130.8

Wav

enu

mb

er /

cm-1

Magnetic field / Gauss

70 Gauss

15130.80 15131.70

The determined g-factors: lower: gS = 2.0215 (fixed) upper: gS = 1.892(26) gLζed = 0.214(51)

(σ:2+3/π:1+2) pair Zeeman splitting: transition to (2E’1/2, J = 0.5)

0 100 200 300 40015131.66

15131.67

15131.68

15131.69

Magnetic field / Gauss

En

ergy

/ c

m-1

σ-pump　 : ●

π-pump　 : ●

Calc : ―

MJ 　 =‐0.5

MJ 　 = +0.5

Perturbation ?

2E’3/2

2E’1/2

2A2’ (K” = 0, N” = 1)

J’ = 1.5

J’ = 1.5

J’ = 0.5

J” = 0.5J” = 1.5

0.0246cm-1

QRR Q

Q P

2E’3/2 ← 2A2’ : 7 transitions

　 Assigned line pairs from the Zeeman splittings

σ-pump: ΔMJ = ±1

π-pump: ΔMJ = 0

σ-pump: ΔMJ = ±1

π-pump: ΔMJ = 0

2E’1/2 ← 2A2’ : 15 transitions

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

N2O5 → NO3 + NO2



NO2

⑤


INTENSITY×5

0 + 950 cm-1 band ：ν1


How about the vibronic bands?

NO2

N2O5 → NO3 + NO2

　 High-resolution LIF spectra 14NO3 0 + 950 cm-1 band and 14NO2

NO2

R (2)

R (0)

R (4)P (2)

0.2 cm-1 Resolution ： 0.0007 cm-1

N2O5 → NO3 + NO2

NO2

Small signal, large background → difficult to analyze

NO3 signal Resolution ： 0.0007 cm-1


15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

15000 　　　 15200 　　　 15400 　　　 15600 　　　 15800 　　　 16000 　　　 16200 　　　 16400 Wavenumber / cm-1

NO2

N2O5 → NO3 + NO2


0 + 770 cm-1 band ： 2ν4



INTENSITY×5


N2O5 → NO3 + NO2

NO2

0.2 cm-1Resolution ： 0.0007 cm-1


N2O5 → NO3 + NO2

0.0246 cm-1

　 High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2 Resolution ： 0.0007 cm-1

Large signal, small background, compared with 0 + 950 cm-1 band

0 G

12 G

25 G

37 G

50 G

62 G

J’ = 1.5

MJ

+ 1.5

+ 0.5

- 0.5

- 1.5

- 0.5

+ 0.5

+ 0.5

- 0.5

- 1.5

J” = 0.5

+ 1.5

π - pump (H // E), ΔMJ = 0

　 Zeeman Splitting at 15872.42 cm-1 line pair

J” = 1.5

0.0246 cm-1

0.0246 cm-1

N2O5 → NO3 + NO2

0.0246 cm-1

R (0.5) Q (1.5)

　 High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2 Resolution ： 0.0007 cm-1

2E’3/2

2E’1/2

X 2A2’ (ʋ”=0, K” = 0, N” = 1)

J’ = 1.5

J’ = 1.5

J’ = 0.5

J” = 0.5J” = 1.5

0.0246cm-1

QRR Q

Q P

Summary

We have observed high-resolution fluorescence excitation spectra of 14NO3 B-X transition.

(1) 0-0 band [15070 – 15145 cm-1]

(2) 0+770 cm-1 band [15872 – 15874 cm-1] *

(3) 0+950 cm-1 band [16048– 16055 cm-1] * (* Not full region.)

Rotational assignment is difficult except the transitions from the X 2A2’ (K” = 0, N” = 1) levels. (0.0248 cm-1 pairs)

Unambiguous assignment of these 0.0248 cm-1 pairs is completed from the observed Zeeman splittings.

How about 15NO3?

MI14

Acknowledgement

Prof. Masaru Fukushima (Hiroshima City University) for his LIF spectrum of 15NO3.

Ms. Kanon Teramoto and Mr. Tsuyoshi Takashino (Undergraduate students, Kobe University) for their help.

Thank you for your attention!

Prof. Masaaki Baba (Kyoto University) for experimental setup at early stage.

How about 15NO3?

MI14

Electronic states of NO3

B 2E’

A 2E”

X 2A2’

~ 15100 cm-1

(~ 662 nm)

~ 7000 cm-1

(~ 1430 nm)

E”

E’

A2’

A2” LUMO

SOMO

NO3 …Planer triangle ⇒ D3h

　　　　　 Radical Doublet⇒

(Gaussian03, RHF/6-31g)

　 Vibrational Assignment

15000 　　　　　　 15400 　　　　　　 15800 　　　　　　 16200 　　　 Wavenumber / cm-1

0 + 950 cm-1 bandM. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)

振動モー

ド

既約表現

遷移波数 (cm-1)

X[1] [2] A[3] B

ν1 a1’ 1060 780 950

ν2 a2” 762 710

ν3 e’ 1480 (?) 1435

ν4 e’ 380 530 ~ 385

2ν4

ν1

0 + 770 cm-1 band

[1] T. Ishiwata et al., J. Phys. Chem., 87, 1349 (1983)[2] R. R. Friedl et al., J. Phys. Chem., 91, 2721 (1987)[3] T. J. Codd et al., 68th Int. Symp. Mol. Spectrosc., WJ05 (2013)

Normal Mode of NO3

　　　　 +　　 - 　　　　 -

-　　　　　　 ν2

　　 A2”

　　　　　　 ν1

　　 A1’

　　　 ν3a

E’

　　　 ν3b

　　　 ν4a

E’

　　　 ν4b

　　　 E’ 　 ν = E’

a1’, a2’, e’

B state

Vibrational level

Vibroniclevel

0 - 0 band

Complicated structure of the 662 nm band

Vib. mode FrequencyAnharmonic

constant

ν1 (a1’)

ν2 (a2”)

ν3 (e’)

ν4 (e’)

772.73

713.59

1688.12

511.20

– 4.603

– 10.268

0

+ 4.785

[Codd et al., 67th OSU meeting, TI01 (2012)]

The A state vibrational frequencies in cm-1

X 2A2’

A 2E”

B 2E’ {

15070 – 15145 cm-1 region: 10 ~ 15 E’-type levels

Complicated structure of the 662 nm band:(mainly) vibronic interaction with dark A state??

7060 cm-1

E” × A2” = E’

15100 cm-1

B 2E’ ：　 Hund’s coupling case(a)

J RP

S

LΛΣ

z(c)

x(a)=y(b)

K NJ

R

L

S

z(c)

x(a)=y(b)

X 2A2’(v=0) ：　 Hund’s coupling case(b)

good quantum number :

Λ, S, Σ, J, P, MJ , K

good quantum number :

N, K, S, J, MJ 　

　 Hund’s Couplig Case

Rotationally-resolved high-resolution laser spectroscopy of the B 2 E’ – X 2 A 2 ’ transition...

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