1. FTIR Spectroscopy of the n4 bands of 14NO3 and 15NO3
(Okayama Univ., Hiroshima City Univ.)
R. Fujimori, N. Shimizu, J. Tang,
K. Kawaguchi, T. Ishiwata

2. Infrared study of NO3
K+1
Four fundamental bands
n3+n4.
n1 ; inactive
n2 ; Friedl and Sander(1987)
n3 ; very weak intensity
n4 ; Only Matrix isolation observation
　（Beckers, Willner, Jacox. 2009)
1127
1492
K+2
n4.
K+3 K
Gr.
DK=3 CD
Present study ; first gas-phase spectroscopy of n4
Determination of C0 from DK=3 Combination Difference
( selection rule DK = ±1 for n4,
combined with other measurements)
Calculation of inertial defect

3. Experimental setup 0.006 cm-1 resolution Effective path length :48-m
Liq. He
Si bolometer

4. Detector part – Silicon Bolometer Dewar temperature 4.2 K to 1.7 K

5. Monitoring of NO3 concentration by HeNe laser
Absorption spectrum of the NO3 B-X band
Sander, J. Phys. Chem. (1986)
discharge Off
10 % absorption
Absorption of HeNe Laser
(3-m path length)
discharge On

6. Observed spectrum of 14NO3 radical

7. Analysis 1. n4 band 114 lines PP(N,K) K=5 ～ 29
2. DK=3 ground state combination differences
n4 (365), n3+n4-n4 (1127), n3+n4 (1492)
3. n4 combination differences
n3+n4-n4 (1127), n3+n4 (1492)
4. DK=0 ground state combination differences
n3+n4 (1492) rQ(N+1,K) and rR(N,K)
pQ(N-1,K) and pP(N,K)

8. Combination differences for DK=3 and n4
n3 + n4 13 14
n3 hot band of 15NO3 was newly observed
1127 cm-1
1492 cm-1 n4 13 14
n4 combination
differences
365 cm-1 band Gr
DK = 3 combination differences
K = 12 15

9. Statistical weight in Analysis
1. n4 band 114 lines PP(N,K) K=5 ～ 29
Weight = 1 (accuracy cm-1)
2. DK=3 ground state combination differences
n4 (365), n3+n4-n4 (1127), n3+n4 (1492)
Weight = 1/3
3. n4 combination differences
n3+n4-n4 (1127), n3+n4 (1492)
Weight = 1/2
4. DK=0 ground state combination differences
n3+n4 (1492) Including diode laser data

10. 14NO3 and 15NO3 molecular constants(1)
(Ground state)
14NO 　　　　　　　 15NO3
present previous 　present
B (86) (63)　 (14)
C 　 (57) [ ] (89)
DN ☓ (13) (12) (25)
DNK☓ (26) (27) (65)
DK ☓ (18) [0.1034] 　 (52)
ebb (20) (13) (26)
ecc (14) [0.0] [ ]
DKx105(calc)
sfit= cm-1

11. 14NO3 and 15NO3 molecular constants(2)
(n4 state) 14NO3 　　　　　　　 　15NO3 　　　　　
present previous present
n (35) (43) (59)
B 　 (41) (60) (90)
C (28) (40) (36)
DN ☓105　0.0924(16) (23) (44)
DNK☓ (41) (58) (13)
DK ☓ (28) (40) (97)
Cz (14) (15) (23)
hN☓ (21) (28) (13)
hK☓ (27) (36) (13)
q (15) (22) (66)
aeff (44) (36) (50)
ebb (36) (36) (53)
ecc (26) [0.0] (33)

12. Inertial defect of planar symmetric top molecule
harmonic frequencies and z3
Jagod and Oka (1990, JMS)
Check of vibrational assignment

13. Inertial defect in BF3 (example, data Maki et al. JMS )
Dobs=Ic-2 Ib
amu Å2
v1 v2 v3 v obs calc obs-calc % % % %
%(max)

14. Inertial Defects D (amu Å2) of NO3
D=Ic - 2Ib
　　　　Obs. Calc. O-C Gr
(0001)
(1001) (
(0011)　
x3 + x4 = 0 (D3h )
n1 (1050), n2 (762)
n3 (1127), n4 (365)
8 %
0.7 %
21 %
24 % n4
n1+n4
3n4
n3+n4
1492 band x3 + x4 ≠ 0 　not in D3h (Jahn-Tellar effect )
large p34 [splitting in K=1], eaa-ebb≠0
In this calc, if n3 = 1492, D3 calc = 0.237
Disagreement with observed D (35%)

15. Relative infrared intensity
n3+n4(1492 band) = 1.00
band 　 Obs.　Calc.（Stanton）
ν4 (365 cm-1)
3ν4 (1173)
ν1+ν4 (1413)
ν3+ν4 (1492)
ν3+2ν4(1927) 　 　　
J. F. Stanton, Molecular Physics, (2009)
Agreement within factor 2 except for ν3+2ν4

16. Summary 1. Measurement of the n4 band of NO3 Present 365.7871 cm-1
Matrix cm-1
Isotope shift (14N - 15N) = cm-1
2. Determination of C0
(67) cm-1 14NO3
(11) cm-1 15NO3
3. Calculations of Inertial defect

17. Inertial defect in SO3 (example, data Maki et al. JMS )
v1 v2 v3 v obs calc obs-calc
Dobs=Ic-2 Ib
amu Å2