1. High-resolution laser spectroscopy
RF02
High-resolution laser spectroscopy
of the B ← X transition of 14NO3 radical:
Vibrationally excited states of the B state
Shunji Kasahara1, Kohei Tada1, Michihiro Hirata1,
Takashi Ishiwata2, and Eizi Hirota3
1 Kobe University, Japan;
2 Hiroshima City University, Japan;
3 The Graduate University for Advanced Studies, Japan;
71st International Symposium on Molecular Spectroscopy
@ Champaign-Urbana, Illinois, The United States
23rd June 2016

2. Absorption spectrum of 14NO3 (Visible)
　Introduction
NO2 + O3 → NO3 + O2
N2O5 ⇄ NO3 + NO2
B 2E’ ： …(4e’)3 (1e’’)4 (1a2)2 ~ cm-1
A 2E’’： …(4e’)4 (1e’’)3 (1a2)2 ~ cm-1
X 2A2’： …(4e’)4 (1e’’)4 (1a2) cm-1
D3h
2NO2
HNO3 + R etc.
NO2　+ O
NO　+ O2
+ NO
+ RH
NO3
+ hν
Absorption spectrum of 14NO3 (Visible)
J. Chem. Soc. Faraday 1176, 785 (1980).
Wavenumber / 1000 cm-1 20 15 10 5
NO2 + O 　　　　NO3 NO + O2
Vibronic Band
~ cm-1
(~ 625 nm)
O2 (b 1Σg+)
B 2E’
0-0 band
~ cm-1
(~ 662 nm)
B – X transition
O2 (a 1Δg)
A 2E’’
662 nm
O2 (X 3Σg-)
X 2A2’
reaction coordinate
K. Mikhaylichenko et al., J. Chem. Phys., 105, 6807 (1996)

3. Photochemistry of NO3 radical: photo-dissociation
NO3 is photolyzed to NO2 + O or NO + O2 in ≤ 630 nm (≥ cm-1) region.
Abs. spectrum of NO3
NO3 + hν
→ NO + O2
→ NO2 + O
Inter-electronic interaction is important to the photolysis pathways.
The vibrationally excited B 2E′ state should be interesting spectroscopically.
“bright state”: B 2E′ state
“first and second excited states”:
(degenerated) A 2E″ state
Magnotta, and Johnston,
Geophys. Res. Lett. 7(10), 769 (1980).
Xiao, Maeda, and Morokuma,
J. Chem. Theory Comput. 8, 2600 (2012).

4. Laser-Induced Fluorescence (LIF) Spectra of NO3 B-X transition
Tada, Kashihara, Baba, Ishiwata, Hirota, and Kasahara, J. Chem. Phys. 141, (2014).
14NO3
15NO3
15000
15500
16000
16500
Wavenumber / cm-1
000
110
420
110 Δ
N2O5 → NO3 + NO2
420
000
Tada, Teramoto, Ishiwata, Hirota, and Kasahara, J. Chem. Phys. 142, (2015).
Fukushima and Ishiwata, 67th Int. Symp. Mol. Spectrosc. TI06 (2012).
Vibrational assignment by Professor Fukushima (Hiroshima City University)

5. Summary of 0-0 bands： Assigned line pairs of 14NO3 and 15NO3
cm-1
2E′3/2 ← X 2A2′
2E′1/2 ← X 2A2′
2E′1/2 ← X 2A2′
Wavenumber / cm-1
2E′3/2
2E′1/2
X 2A2′ (k″ = 0, N″ = 1)
J’ = 1.5
J′ = 1.5
J′ = 0.5
J″ = 0.5
J″ = 1.5 Q R P
cm-1
14NO3: Tada, et. al., J. Chem. Phys. 141, (2014)
15NO3: Tada, et. al., J. Chem. Phys. 142, (2015)

6. LIF Spectra of NO3 B-X transition
Tada, Kashihara, Baba, Ishiwata, Hirota, and Kasahara, J. Chem. Phys. 141, (2014).
14NO3
15NO3
15000
15500
16000
16500
Wavenumber / cm-1
000
110
420
110 Δ
N2O5 → NO3 + NO2
cm-1 band
420
000
15000
15500
16000
16500
Intensity×5
Tada, Teramoto, Ishiwata, Hirota, and Kasahara, J. Chem. Phys. 142, (2015).
14NO2
R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)
Fukushima and Ishiwata, 67th Int. Symp. Mol. Spectrosc. TI06 (2012).
Vibrational assignment by Professor Fukushima (Hiroshima City University)

7. Experimental setup I Absolute wavenumber mesurement system
(Accuracy : cm-1)
Single mode laser ( Γ = cm-1 )
PBS PD BS
Nd:YVO4
Laser
Ring Dye
Laser
I2 Cell
532 nm
around 660 or 625 nm
EOM
Etalon D
Molecular Beam
(Typical linewidth : cm-1)
Photon Counter
PMT
Liq. N2
Filter
Pulsed Nozzle
N2O5 + Ar
Computer
NO2 + Ar
BS : Beam splitter
PBS : Polarization beam splitter
EOM : Electro-optic modulator
PD : Photo diode
PMT : Photomultiplier tube
Heater 300 ℃
Heater off
Slit
(2 mm)
Mirror & Magnet
N2O5 → NO3 + NO2
Skimmer
(ϕ= 2 mm)
Pump
Pump

8. LIF spectra of 14NO3 and 14NO2 0 + 770 cm-1 band Resolution：0.2 cm-1
15000　　　 　　　 15400　　　 15600　　　 　　　 16000　　　 　　　 16400
Wavenumber / cm-1
cm-1 band
N2O5
→ NO3 + NO2
M. Fukushima et al., 67th Int. Symp. Mol. Spectrosc., TI06 (2012)
15000　　　 　　　 15400　　　 15600　　　 　　　 16000　　　 　　　 16400
Wavenumber / cm-1
INTENSITY ×5
NO2
R. E. Smalley et al., J. Chem. Phys., 63, 4977 (1975)

9. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
0.3 cm-1
N2O5 → NO3 + NO2 *
* NO2 signal
Wavenumber / cm-1
R(4)
P(4)
∆N(N″)
NO2
R(2)
P(6)
cm-1 band
Trot ~ 15K
P(8)
P(2)
P(10)
R(0)
P(12)
P(14)
Wavenumber / cm-1 8

10. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
N2O5 → NO3 + NO2
NO3 signal
NO2
Wavenumber / cm-1 9 1

11. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
Observed spectrum
Very complicated
Less regularity
Wavenumber / cm-1
15890 − cm-1 (30 cm-1)
Assignment
Ground State Combination Difference
Zeeman splitting pattern
これだけではなんとも言えないので、おそらくの物も見せる。
Wavenumber / cm-1

12. Ground State Combination Difference
The matrix elements of X 2A2′ (υ = 0) state of NO3 J 1 3 5
0.5
1.5
2.5
3.5
4.5
5.5
k=0 N
Energy / cm-1 10 15
a = b
N = J － S c K
Hund’s coupling case (b)
Molecular constants of NO3 in the X 2A2′ (υ = 0) state
J=1.5
J=0.5
N=1
cm-1
Kawaguchi et al., Chem. Phys., 231, 193 (1998).
Constants (cm-1) B
(63) C
B/2
DN×105
0.1113(12)
DNK×105
(27)
DK×105
-(2DN+3DNK)/4
εbb
(13)

13. Selection rules of B-X transition (perpendicular band)
　 B - X transition: Selection rules
Transitions to the 2E′1/2 and the 2E′3/2
Selection rules of B-X transition (perpendicular band)
ΔK = ±1, ΔJ = 0, ±1
X 2A2′ (υ″=0, k″=0)
J″=0.5
J″=1.5
J′=0.5
J′=1.5
2E′1/2 (k′=1) rR rQ
2E′3/2 (k′=1) rP
The nomenclature: ∆k∆J
B state: Hund’s coupling case (a)
spin−orbit interaction →
X state: Hund’s coupling case (b)
spin−rotation interaction →
These three transitions are detected as two rotational lines with cm-1 spacing.
cm-1

14. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
Transitions from the X 2A2′ (υ = 0, N=1) levels
cm-1 spacing line pair
Wavenumber / cm-1
15890 − cm-1 (30 cm-1)
0.3cm-1
固まっているというのは0－0と同じ。だけど、固まった部分が綺麗になっているのではなく、複数ありそうな感じがする。その理由としてはJHもしくは、もともと2つの振電バンドが重なっている事が考えられる。
Wavenumber / cm-1

15. Unambiguous rotational assignment → Zeeman splitting observation
　High-resolution LIF spectra 14NO cm-1 band and 14NO2
− cm-1 (0.3 cm-1)
Rotational lines > 2000
( cm-1 )
FWHM~30 MHz
Resolution
≈ 30 MHz (0.001 cm-1)
Accuracy of the absolute wavenumber
≈ 3 MHz ( cm-1)
Unambiguous rotational assignment
→ Zeeman splitting observation
cm-1
Wavenumber / cm-1

16. Experimental setup: Detection of the Zeeman splitting
Selection rules for the Zeeman effect H
ΔMJ =0
ΔMJ =±1
π-pump (H // E)
σ-pump (H⊥E）
Photomultiplier tube
H: Magnetic field vector, E: Polarization of laser
Observed Zeeman splitting at the 0 – 0 band region
0 G
70 G
125 G
190 G
245 G
305 G
360 G
H =
π-pump
σ-pump
Electromagnet
Fluorescence collecting
mirror system
Laser beam
コイル付近の説明。Zeemanを二種類とれる。今回は全部パイ。
Electromagnet
Wavenumber / cm-1

17. Zeeman Hamiltonians and matrix elements
The X 2A2’ state: HZ = gS μB H·S
The B 2E’ state: HZ = gS μB H·S + gL μB H·Leff
μB (= ×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>.
Refs: Endo et al., J. Chem. Phys., 81, 122 (1984)
Hirota, High-Resolution Spectroscopy of Transient Molecules, Springer (1985)
Tada, Kashihara, Baba, Ishiwata, Hirota, and Kasahara, J. Chem. Phys. 141, (2014)

18. Unambiguous rotational assignment → Zeeman splitting observation
　High-resolution LIF spectra 14NO cm-1 band and 14NO2
− cm-1 (0.3 cm-1)
Rotational lines > 2000
( cm-1 )
FWHM~30 MHz
Resolution
≈ 30 MHz (0.001 cm-1)
Accuracy of the absolute wavenumber
≈ 3 MHz ( cm-1)
Unambiguous rotational assignment
→ Zeeman splitting observation
cm-1
Wavenumber / cm-1

19. Zeeman splitting of the B 2E′1/2 - X 2A2′ transitions
π-pump (H // E, ΔMJ =0)
Observed Zeeman splitting at the 0 − 0 band region
π-pump (H // E, ΔMJ =0)
1+2 splitting
ΔkΔJk″(J″)
rQ0(0.5)
rP0(1.5)
H=0 G
H=0 G
70 G
40 G
125 G
190 G
60 G
245 G
右は0－0で既に帰属の出来ている物。それと同じなので帰属できる。
305 G
85 G
360 G
Wavenumber / cm-1
Wavenumber / cm-1

20. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
Transitions from the X 2A2′ (υ = 0, N=1) levels
cm-1 spacing line pair
Wavenumber / cm-1
15890 − cm-1 (30 cm-1)
固まっているというのは0－0と同じ。だけど、固まった部分が綺麗になっているのではなく、複数ありそうな感じがする。その理由としてはJHもしくは、もともと2つの振電バンドが重なっている事が考えられる。
Wavenumber / cm-1

21. Zeeman splitting of the B 2E′3/2 - X 2A2′ transitions
π-pump (H // E, ΔMJ =0)
Observed Zeeman splitting at the 0 − 0 band region
π-pump (H // E, ΔMJ =0)
2+3 splitting
ΔkΔJk″(J″)
rQ0(1.5)
H=0 G
rR0(0.5)
H=0 G
60 G
70 G
125 G
Wavenumber / cm-1
π-pump (H // E, ΔMJ =0)
190 G
245 G
H=0 G
305 G
60 G
360 G
Wavenumber / cm-1
Wavenumber / cm-1

22. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
Transitions to the 2E′3/2 (J′=1.5)
Transitions to the 2E′1/2 (J′=0.5)
2E′3/2
2E′1/2
X 2A2′ (k″ = 0, N″ = 1)
J’ = 1.5
J′ = 1.5
J′ = 0.5
J″ = 0.5
J″ = 1.5 Q R P
cm-1
Wavenumber / cm-1
15890 − cm-1 (30 cm-1)
これだけではなんとも言えないので、おそらくの物も見せる。
Wavenumber / cm-1

23. High-resolution LIF spectra 14NO3 0 + 770 cm-1 band and 14NO2
15860 − cm-1 (30 cm-1)
Transitions to the 2E′3/2 (J′=1.5)
Transitions to the 2E′1/2 (J′=0.5) * * * * *
2E′3/2
2E′1/2
X 2A2′ (k″ = 0, N″ = 1)
J’ = 1.5
J′ = 1.5
J′ = 0.5
J″ = 0.5
J″ = 1.5 Q R P
cm-1
Wavenumber / cm-1
15890 − cm-1 (30 cm-1) * * * * * * *
固まっているというのは0－0と同じ。だけど、固まった部分が綺麗になっているのではなく、複数ありそうな感じがする。その理由としてはJHもしくは、もともと2つの振電バンドが重なっている事が考えられる。 * *
Wavenumber / cm-1
* Probably : S/N ratio is not enough for the Zeeman measurement

24. Summary This study: LIF spectrum of the B − X transition
15900 cm-1 band
LIF spectrum of the B − X transition
We have observed high-resolution fluorescence excitation spectra of 14NO3 B-X transition for the cm-1 band [15860 – cm-1].
Observed rotational line are weak compared with the ones of 0-0 band.
In the observed region, more than 3000 rotational lines were found.
Rotational assignment is difficult except the transitions from the X 2A2’ (K” = 0, N” = 1) levels. ( cm-1 pairs)
Unambiguous assignment of these cm-1 pairs is completed from the observed Zeeman splittings.
The transitions to the 2E’3/2 and 2E1/2 were observed as the several pairs and these pairs make groups. (not random distribution)
Resolution: 0.2 cm-1
N2O5 → NO3 + NO2
Pyrolysis: 00 10 1
15000
15500
16000
16500
NO3 + NO2 [1] 40 2 *
* NO2 signal * * * * * *
Wavenumber / cm-1
ここではどうなっているのか。
Wavenumber / cm-1
Wavenumber / cm-1

25. Acknowledgement
Prof. Masaaki Baba (Kyoto University) for experimental setup at early stage.
Ms. Hitomi Matsubara and Mr. Tsuyoshi Takashino (Undergraduate students, Kobe University) for their help.
Prof. Masaru Fukushima (Hiroshima City University) for his LIF spectrum of 15NO3.
Japan Society for the Promotion of Science for the financial support.
Thank you for your attention!

27. < 2E′3/2 – X 2A2′ transition (0 – 0 band) >
　Zeeman effect around cm-1
2E′3/2 – X 2A2′ transition
< 2E′3/2 – X 2A2′ transition (0 – 0 band) >
J′ = 1.5 MJ
+ 1.5
+ 0.5
0.5
1.5
- 0.5
J″ = 0.5
J″ = 1.5
cm-1
rQ0(1.5)
rQ0(1.5)
rR0(0.5)
rR0(0.5)
cm-1
Magnetic field
cm-1
0 G
40 G
70 G
Tada et al., J. Chem. Phys. 141, (2014).
Wavenumber / cm-1
Wavenumber / cm-1

28. Vibrational Assignment
M. Fukushima et al., 67th Int. Symp.
Mol. Spectrosc., TI06 (2012)
cm-1 band
0 - 0 band ν1
15000　　　　　　15400　　　 　　　15800　　　 　　　16200　　　
Wavenumber / cm-1
　　　 E’ 　 ν = E’
a1’, a2’, e’
B state
Vibrational level
Vibronic
level
cm-1 band
2ν4
Normal Mode of NO3
　　　　 +
　　-　　　　 - -
　　　　　　ν2
　　A2”
　　　　　　ν1
　　A1’
　　　ν3a E’
　　　ν3b
　　　ν4a
　　　ν4b 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
380
530
~ 385
[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)

29. Complicated structure of the 662 nm band
Vib. mode
Frequency
Anharmonic
constant
ν1 (a1’)
ν2 (a2”)
ν3 (e’)
ν4 (e’)
772.73
713.59
511.20
– 4.603 –
[Codd et al., 67th OSU meeting, TI01 (2012)]
The A state vibrational frequencies in cm-1 {
B 2E’
15100 cm-1
A 2E”
7060 cm-1
E” × A2” = E’
15070 – cm-1 region: 10 ~ 15 E’-type levels
Complicated structure of the 662 nm band:
(mainly) vibronic interaction with dark A state??
X 2A2’