1. Analysis of high resolution infrared CW-CRDS spectra of ozone in the 6000-6750 cm-1 spectral region
A. Barbe, M.R. De Backer-Barilly, Vl.G. Tyuterev, D. Romanini1, S.Kassi1 , A. Campargue1
Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 6089
Université de Reims Champagne – Ardenne
France
1 Laboratoire de Spectrométrie Physique, UMR CNRS 5588, Université Joseph Fourier, Saint Martin d’Hères, France

2. The compact fibered CW-CRDS spectrometer (Grenoble) nm ( cm-1) Typical sensitivity 310-10 cm-1
6nm/diode
40 diodes
Laser diode
Lambdameter
n=f(T,I)
Optical isolator
Coupler
-50 50
100
threshold
Laser OFF AO
Modulator
laser ON
Photodiode

3. Illustration of the achieved sensitivity:
The example of the a1Δg (0)−X3Sg−(1) of O2
k=8×10-31cm/molec
Chem. Phys. Lett. 409 (2005) 281–287

6. Intensity calculations

7. Region ( ) 6720 cm-1
Observed absorption coefficient (10-6 cm-1)

8. E/hc (cm-1) (412) 6800 (242) (520) (171) (233) 6700 (313) (350) 6600
Ka = 6
Ka = 5
Ka = 10, 11
Ka = 9, 10
Ka = 12
Ka = 11
Ka = 7,8,9
Ka = 6,7,8
Ka = 5,6,7
Ka = 4,5,6
Ka = 3
E/hc (cm-1)
Ka = 0,1,2
(313)

9. % on (520) in (233)

10. % on (520) in (242)

12. Spectroscopic parameters (cm-1)
(350)
(233)
(171)
(520)
(242)
(412)
EVV
(10)
(80)
(f)
(21)
(29)
(11)
A-(B+C)/2
(85)
(67)
3.37 (f)
(22)
(14)
(38)
(B+C)/2
(14)
(70)
(f)
(54)
(11)
(21)
(B-C)/2
(30)
(95)
(f)
(11)
(79)
(f) DK
103 g
(13)
(14)
(22)
DJK
105
(53)
(23) DJ
106
(39)
(33)
(10) dJ
(28)
(28) dK
(42)
(64) HK
(69)
HKJ
107
(19)
Coupling parameters

13. Statistics for rovibrational transition calculation
(233)(010)
(233)(000)
(242)(000)
(520)(000)
Band center (cm-1)
J max 37 46 33
Ka max 9 12 7
Number of transitions
322
797
r.m.s. (103) (cm-1)
3.7
8.5
7.5

14. Transition moment operator parameters (Debye)
Value
Number of transitions
(J max, Ka max)
rms deviation (%)
2n1 + 3n2 +3n3 band
d1 (×104)
(35)
213
(36, 13)
16.7 %
d2 (×108)
(23)
d3 (×107)
(28)
d6 (×107)
(16)
d7 (×107)
(16)
2n1 + 4n2 + 2n3 band
d1 (×105)
(25)
102
(42, 9)
24.0 %
d5 (×106)
(49)
2n1 + 3n2 +3n3 – n2 band
d1 (×103)
(23)
104
(33, 9)
23.4 %
d2 (×107)
(28)
d4 (×106)
(10)

15. Statistics for line intensities
2n1 + 3n2 +3n3 band
2n1 + 4n2 + 2n3 band
2n1 + 3n2 +3n3 – n2 band
Deviation
Number of lines
158 (74.2 %)
79 (77.4 %)
74 (71.2 %)
40 (18.8 %)
18 (17.6 %)
26 (25 %)
15 (7 %)
5 (5 %)
4 (3.8 %)
rms = 16.7 %
rms = 24.0 %
rms = 21.1 %

16. Final comparison between Observed and Calculated spectrum

17. Comparison between Obs. and Calc. spectrum
in the P branch of 21+32+33 (J’= 14)
141
142
143
144
145
360
371
Observed spectrum
Calculated spectrum
CO2
H2O

18. E (cm-1) Nb DE
O-C
vib J Ka Kc 1
-10.8
233
-8.8 3 2
1.4
-7.6 5
0.2 7
0.3
-4.3 9
5.8 11
0.5
-2.6 13 4
1.5 15
0.6 17
1.1 19
0.8 21
1.0
2.5 23
1.8
-3.3 25
3.8
-3.0 27
0.7
-1.2 29
1.6
-5.5 31
2.7 33
9.7 35
-8.9
-8.0
-7.4
2.9
-5.4
-7.7

19. Global survey of the 6000 – 6200 cm-1 spectral range
2n1+2n2+3n3 #
n1+2n2+4n3
n1+5n3 #
2n1+3n2+3n3-n2
3n2+4n3
5n1+n2
Global survey of the 6000 – 6200 cm-1 spectral range
7 different diodes : without impurities : CO2, H2O, CO

20. Observing and assigning B type bands (ΔKa= ± 1) in this high level range represents an challenge.
With previous work done with the F.T.S, the highest observed bands were 2n1+2n3( 4141 cm-1) and 2n1+n2+2n3 (4783 cm-1).
In general , FOR OZONE, this type of band is much more difficult to assign than A type bands, were strong compressed R branch appear, for several reasons:
They are much weaker than A type bands at a given energy level range.
They extend over a much larger spectral range, and , as a consequence, are never totally observed , being overlapped by stronger A type bands, and often partly hidden by impurities, like H2O,CO2,CO…
The general shapes of theses bands are difficult to reproduce in a first attempt, as 6 type of transitions may be observed, and the introduction of unknown additional transition moment parameters is obligatory to reproduce line intensity observations.( as example μ 5 terms must be introduce to “ reduce” Q branches which are not visible in our spectra ).

21. Calculated spectra of 1+22+43 in 3 cases
(normalisation on observed lines in the 6155 cm-1 region)
All  of A and B bands
All  of B band; A =0
Only 1 for B band ( 5=0):

22. Observed and calculated spectrum of the n1 + 2n2 +4n3 band
in the 6156 – 6157 cm-1 range *
Observed
Calculated
CO2
301
312
235
226
266
257
212
221
232
241
291
280
252
261
192
201
Wavenumber (cm-1)
Absorption Coefficient (a.u.)

23. (331-000) the weakest band observed so far
310-28 cm-1 molecule cm-2
Observed spectrum
Calculated (331)-(000)
Calculated (124)-(000)
CO2

24. Vibrational Assignment
Assigned transitions in the range 6000—6900cm-1
Nature of the work
Vibrational Assignment
Band center
Number of transitions
J max
Ka max
completed
350 37 11
138 40 4
531 43 10 *
122 29
520 44 14 *
498 49 7
116 23 6
In progress
992 39 12
593
548 36 65 27 2
398
483 * 22 33 * ;
399 46 9
284
TOTAL :
5959

25. Observed – Predicted (cm-1)Range 4250-5520
Vibrational state
Observed – Predicted (cm-1)Range
202
+0.021
301
023
+0.288
122
-0.030
221
+0.035
014
+0.292
320
-0.131
113
+0.279
212
+0.139
311
+0.433
005
+0.411
104
+0.584
203
-0.090
302
+0.656
123
-0.094
401
+0.050
015
+0.136
Vibrational state
Observed – Predicted # (cm-1)Range
114
+0.558
015
-0.396
105
0.896
232
-1.526
105/303
+0.320
510
+0.808
223
-1.748
124
-0.397
331
+0.712
025
-2.192
501
+0.243
223/313
+0.428
421
-0.227
205
-0.566
233/143
5.162
520
-1.902
242
2.757
Vl.G. Tyuterev, H. Seghir, A. Barbe, S.A. Tashkun, « Ozone molecule : high energy resonances, consistency of variational and perturbative calculations and complete vibration assignments up to dissociation », HRMS, Praha 2006

26. Conclusion
This work , thanks to the high sensitivity of the experimental set-up (CW-CRDS) allows to observe many weak rovibrational transitions of ozone. All the « relatively strong or of medium intensity « are rotationally undoubtedly assigned. It confirms previous work done with FTS, that is to say, that above 3300 cm-1,the simplified scheme of ozone, including poylads corresponding to the same value of v2, with Darling-Dennison resonances between v1,v2,v3 and v1±2,v2,v3 Ŧ 2 states and coriolis resonances between v1,v2,v3and v1 Ŧ 1,v2,v3 ± 1 states is no more valid : large vibrational couplings arise between all states in a neighborhood, even with large value of v2. As a result, predictions of the strengths of interactions between various partners become a real challenge, as the number of possibly interacting states become obviously larger and larger as far as energy is increasing. Remember that highest observations are near 7000 cm-1, the dissociation limit being near 8600 cm-1. Prediction of rotational constants also is difficult.
Nevertheless, we have been able, in two spectral regions, to complete the works, that is to say find suitable models, for positions and intensities which reproduce correctly ( near the experimental accuracy) the observed spectra.
Consequently, we give for these works not only hamiltonian parameters and transition moment parameters, but also energy levels, corresponding to observed transitions.
It has also been possible to reproduce B type bands, despite the difficulties mentioned during this talk.
A s final conclusion, we will continue to advance theoretically and experimentally, simultaneously, to have a final good understanding of the dipole and potential function of ozone