1. Supersonic Free-jet Quantum Cascade Laser Measurements of 4 for CF 3 35 Cl and CF 3 37 Cl and FTS Measurements from 450 to 1260 cm -1 June 20, 2008 James F. Kelly, Thomas A. Blake, Robert L. Sams Pacific Northwest National Laboratory Richland, WA Arthur Maki Mill Creek, WA

2. 2 Line-of-Sight Free Space Communications quantum cascade laser atmosphere, fog, aerosols, turbulence > km distances gas cell detector Lock laser on side of transition. Apply blue then red (“1”) or red then blue (“0”) FM chirp for bit transmission. Use gas to demodulate laser signal: FM to AM conversion at detector. Use laser wavelength that is less susceptible to atmospheric scattering effects. Provides secure, line-of-sight communications. Need a strong absorber in atmospheric window with sharp rovibrational transitions.

3. 3 Fundamental Vibrational States (cm -1 ) of CF 3 Cl FundamentalCF 3 35 ClCF 3 37 Cl 1 (a 1 )1108.3561108.026 2 (a 1 ) 783.362 782.208 3 (a 1 ) 476.968 469.165 4 (e) 1216.7581216.720 5 (e) 561.109 560.822 6 (e) 347.2

4. 4 Ground State Constants (cm -1 ) of CF 3 Cl CF 3 35 Cl CF 3 37 Cl A0.191 3 a 0.191 3 a B0.111 263 458 b 0.108 461 01 b D J  10 8 1.843 98 b 1.759 3 b D JK  10 8 6.929 7 b 6.724 4 b D K  10 8  4.123 a  4.123 a a) Amrein, et al. Chem. Phys. Lett. 139 82-88 (1987). b) Carpenter, et al. J. Mol. Spec. 93 286-306 (1982). Vibrational assignments checked against ground state combination differences,  F 2 .

5. 5 ExperimentExperiment Chlorotrifluoromethane (CF 3 Cl, Freon-13) purchased from SynQuest Labs. Quantum cascade laser, pulsed, slit-jet molecular beam Laser covers 1215.8 to 1220.6 cm -1 of 4 band. 0.1% CF 3 Cl in Ar, backing pressure 100 to 1000 Torr. 12 cm x 200  m, 7.5 mS pulse duration at 2.88 Hz. Fourier transform spectra of CF 3 Cl 1, 2 5, 4 bands: 20 cm path, 25 & -67 ° C 0.0018 cm -1 resolution. 2, 2 3 bands: 20 cm path, 25 ° C 3.2 m path, 22 ° C 0.0013 cm -1 resolution. 5 band: 9.6 m, 22.4 m path, 22 ° C 0.004 cm -1 resolution.

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10. 10 Term Value Expression: F(J,k,l) = G(v,l ) + B v J(J+1) + (A v  B v ) k 2  kl [ 2A  v   J v J(J+1)   k v k 2  JJ v J 2 (J+1) 2  JK v J(J+1)k 2  KK v k 4 ]  D J v J 2 (J+1) 2  D JK v J(J+1)k 2  D K v k 4 + H J v J 3 (J+1) 3 + H JK v J 2 (J+1) 2 k 2 + H KJ v J(J+1)k 4 + H K v k 6 l-type Resonance Hamiltonian: W 2,2 =  v 4, J, k, l | H/hc | v 4, J, k  2, l  2  = ¼ {q 4 + q J 4 J(J+1) + q K 4 [k 2 + (k  2) 2 ]} {(v 4 +1) 2  (l  1) 2 } ½  {[ J (J + 1)  k (k  1)][ J (J + 1)  (k  1)(k  2)]} ½

11. 11 4 Band 4 Band Use work of Amrein et al. Chem. Phys. Lett. 139 82-88 (1987) as starting point: J ≤ 20, K ≤ 20. Jet spectra improve assignment and fit in the Q- branch region. Present FTS measurements extend out to J = 76 and K = 49. Intensity alternation and ground state combinations used to verify assignments.

12. 12 Rovibrational Constants (cm -1 ) for the 4 Band CF 3 35 Cl CF 3 37 Cl 0 1216.758 284(12)1216.719 91(3)  A  10 3  0.751 04(4)  0.752 52(21)  B  10 3  0.003 797(21)  0.005 89(14)  D J  10 8 0.061 3(7) 0.066(11)  D JK  10 8  0.203 8(24) [  0.20]  D K  10 8 0.218 1(32) [0.22] A  0.151 052 4(4) 0.151 035 6(20)  J  10 6 0.338 2(5) 0.303 7(62)  K  10 6  0.094 7(9) [  0.095] q 4  10 3 0.195 38(11) 0.181 54(24) q J 4  10 8  0.144(4) [  0.14] Jet spectrum: No. lines 339 231 Rms dev. 0.00022 0.00023 FTS spectrum: Jmax 76 41 Kmax 49 20 No. of lines 4060 559 Rms. Dev. 0.00020 0.00021

13. 13 a. P R 3 (10) 1219.4067 cm -1 b. R R 6 (16) 1219.4288 cm -1 c. R R 3 (14) 1219.4344 cm -1 d. R R 0 (12) 1219.4454 cm -1 P 0 = 100 Torr 0.1% CF 3 Cl in Ar 12 cm x 200  m slit 7.5 mS gas pulse duration 2.88 Hz gas pulse rate 0.038 cm -1 /mS laser sweep Single sweep Laser power 45 mW

14. 14 1 and 2 5 Coupling Term 1 and 2 5 Coupling Term  v 1, v 5, J, k, l 5 | H/hc | v 1  1, v 5 +2, J, k  2, l 5  2  = {c 2,2 + c k 2,2 [k 2 +(k  2) 2 ]}  {[J(J+1)  k(k  1)][J(J+1)  (k  1)(k  2)]} ½ Crossing levels: J = 29, K = 18 level of 1 and J = 29, K = 16, l = -2 of 2 5 J = 46, K = 19 level of 1 and J = 46, K = 17, l = -2 of 2 5 …and higher K values. Coupling through a  k = ±2,  l = ±2 matrix element …

15. 15 1 Band 1 Band Giorgianni et al. J. Mol. Spec. 130 183-192 (1988) extended diode laser measurements out to J = 65 for the 1 band. Our measurements go to J = 86 and K = 33. High density of lines and perturbations prevented assignments and fitting of higher transitions. No Q-branch lines used in fit. Only well resolved P- and R-branch lines were included in fit. Transitions with K < 5 not included in fit.

16. 16 2 5 Band 2 5 consists of a parallel band with l = 0 and a perpendicular band with l = 0 and l = ±2. The l = ±2 levels are too weak to see. The perturbations of 1 = 1 are caused by an avoided crossing with the kl < 0 rotational manifold of 2 5. Only R-branch transitions were observed because the P-branch transitions overlapped with 1 band. Fit of the A component indicated that the E component is ~1 cm -1 lower.

17. 17 Rovibrational Constants (cm -1 ) for CF 3 35 Cl 1 2 5 0 2 5 2 0 1108.356 41(4) 1122.854 15(6) 1121.785(10)  A  10 3  0.380 23(28)  0.378 76(40) [  0.37876]  B  10 3  0.566 97(5) 0.095 05(10) [0.09505]  D J  10 8 0.103 4(18)  0.233 0(35) [  0.233]  D JK  10 8 0.483(11) 0.543(18) [0.543]  D K  10 8  1.92(6)  0.211(46) [  0.211]  H J  10 12 0.062 5(19)    H JK  10 12 0.439(16)    H KJ  10 12  2.50(8)    H K  10 12  15.2(4)   A    0.131 28(14) q 5  10 4  [1.34] c 2,2  10 4 0.211(5) c K 2,2  10 7  0.093(6) No. of lines 2746 514 Rms dev. 0.00022 0.00025

18. 18 Rovibrational Constants (cm -1 ) for CF 3 37 Cl 1 2 5 0 2 5 2 0 1108.025 93(8) 1122.299 64(21) 1121.214 8(12)  A  10 3  0.387 58(41)  0.385 7(12) [  0.3857]  B  10 3  0.544 35(15) 0.088 02(32) [0.08802]  D J  10 8 0.123(7) [  0.245] [  0.245]  D JK  10 8 0.254(32) [0.596] [0.596]  D K  10 8  3.04(5) [  0.163] [  0.163]  H J  10 12 [0.06]    H JK  10 12 [0.43]    H KJ  10 12 [  2.5]    H K  10 12 [  15.2]   A   [  0.131 28] q 5  10 4  [1.34] c 2,2  10 4 [0.211] c K 2,2  10 7 [  0.093] No. of lines 711 34 Rms dev. 0.00025 0.00041

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20. 20 3 State and 2 3 Band 3 State and 2 3 Band 3 band is very weak. Burger et al. J. Mol. Spec. 93 55-73 (1982) gives band origin of 3 at 476.973(7) cm -1 from 0.04 cm -1 resolution spectra. Use the 1 – 3 difference band and 2 + 3 – 3 hot band to determine 3 state constants. For the 2 3 band the K structure in the P- and R-branches is sharply peaked; assume the maximum is at K = 2. For the Q-branch the most intense transitions are K = J; assume peak is highest K value divisible by 3. 2 3 band of CF 3 37 Cl band was too weak to get full assignment, but could determine band origin.

21. 21 Rovibrational Constants (cm -1 ) for 3 and 2 3 CF 3 35 Cl CF 3 37 Cl 2 3 3 0 952.406 16(8)a 476.967 54(7) 936.943 61(21) 469.164 85(11)  A  10 3  0.060 59(25)  0.029 28(28) [  0.055 0]  0.027 9(14)  B  10 3  0.140 936(39)  0.067 30(6)  0.135 40(19)  0.064 56(11)  D J  10 8 [0.072] 0.036 9(11) [0.072] 0.050 1(23)  D JK  10 8  0.349(33)  0.126(8) [  0.36] [  0.12]  D K  10 8 0.334(32)  0.003(30) [0.32] [0.00] No. of lines 215 710 41 129 Rms. Dev. 0.00028 0.00025 0.00041 0.00029

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23. 23 2 Band 2 Band Previous results from diode laser measurements of Baldacchini et al. J. Mol. Spec. 130 337-343 (1988). K structure in R-branch not resolved; assume K = 2 for these transitions. K structure in P-branch partially resolved down to J = 25 for CF 3 35 Cl and J = 50 for CF 3 37 Cl. For resolved J structure in P-branch only strong transitions up to K = 48 with K divisible by 3 were used in fit. Low-J Q-branch transitions were assumed to be the largest K value possible divisible by 3.

24. 24 Rovibrational constants (cm -1 ) for 2 and 2 + 3  3 CF 3 35 Cl CF 3 37 Cl 2 2 + 3  3 2 0 783.362 065(35) 781.773 09(6) 782.208 49(7)  A  10 3  0.156 530(52)  0.156 52(16)  0.156 54(9)  B  10 3  0.168 814(15)  0.170 377(14)  0.163 071(17)  D J  10 10  0.073(12) [  0.073] [  0.073]  D JK  10 10  0.99(14) [  0.99] [  0.99]  D K  10 10 4.31(14) [4.31] [4.31] No. of lines 841 175 268 Rms. Dev. 0.00020 0.00026 0.00032

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27. 27 5 Band 5 Band R Q 0 -branch is sharper than other Q-branches because of large q 5 value. Band center agrees with results of Burger et al. Spectrochim. Acta 39A 985-992 (1983); B 5 and q 5 values agree with  -wave results of Carpenter et al. J. Mol. Spec. 93 286-306 (1982). Most Q-branches resolved for J > 20. P- and R- branches are resolved up to kl = +16. High density of lines made it difficult to assign the CF 3 37 Cl transitions.

28. 28 Rovibrational Constants (cm -1 ) for 5 CF 3 35 Cl CF 3 37 Cl 0 561.108 935(12)560.822 21(29)  A  10 3  0.184 774(25)  0.190 5(6)  B  10 3 [0.076 442 9]c 0.076 67(28)  D J  10 8 0.011 68(16) 0.056(7)  D JK  10 8  0.002 26(90) [  0.0022]  D K  10 8  0.082 92(92) [  0.082] A   0.140 514 79(59)  0.141 041 2(35)  J  10 6 0.016 5(10) [0.0165]  K  10 6  0.406 1(11) [  0.406]  JJ  10 12 0.85(18) [0.85]  JK  10 12  1.27(27) [  1.27] q 5  10 4 [0.946 718 28] [0.946718] q J  10 9  0.038(11) [  0.038] q K  10 9  15.1(15) [  15.1] Jmax 86 66 Kmax 70 28 No. of lines 5653 259 Rms dev. 0.00025 0.00052

29. 29 SummarySummary Improved spectroscopic constants for the 4 band using combined QC-laser and jet spectra. Extend J and K values in FTS spectra. Improved spectroscopic constants for the 1 and 2 5 bands. Extend J and K values in FTS spectra. First rotationally resolved infrared measurement of 5 band. Improved spectroscopic constants for 2 and 2 + 3 – 3 hot band. Extend J and K values in FTS spectra. Use 1 – 3 and 2 + 3 – 3 to determine spectroscopic constants for 3 for the first time.