Electric Quadrupole Transitions in the Band of Oxygen: a Case Study Iouli E. Gordon Samir Kassi Alain Campargue Geoffrey C. Toon a 1  g — X 3  g -

Lowest electronic states of O 2 a 1  g X 3 Σ g - M1- Magnetic dipole E2- Electric quadrupole M1, E2 E2 Remote sensing in relation to high-accuracy measurements of atmospheric greenhouse gases such as CO 2 and CH 4 –Uniform mixing of oxygen provides calibration and removes systematic errors –ASCENDS mission Nightglow in planetary atmospheres M1>> E µm 0.76 µm b 1 Σ + g

FTS in Park Falls

Orr-Ewing et al. line list and HITRAN update in November 2009

Lowest electronic states of O 2 b 1 Σ + a 1  g X 3 Σ g - M1, E2 E2 F 1 (J=N+S) F 2 (J=N+S-1) F 3 (J=N-S) 1.27 µm 0.76 µm g

Quadrupole transitions e f e f f e e e f e J=±2J=±2  J=±1  J=0 T(9)S(10) R(9)S(8) P(9)O(10) S(9)S(9) O(9)O(9) N(9)O(8)S(9)R(10) R(9)R(9)P(9)P(9) O(9)P(8)R(9)Q(10) Q(9)Q(9) P(9)Q(8) J N=9 F1F1 F2F2 F3F3 Q(9)R(8) Q(9)P(10) Notation of branches: ΔN(N'')ΔJ(J'')

CRDS measurements in Grenoble laser ON Laser diode Photodiode Lambdameter Optical isolatorCoupler AO Modulator Laser OFF threshold =f(T,I) 6nm/diode 30 DFB diodes Routine sensitivity: cm -1, ie 1 % absorbance for 300 km path length Large dynamic range of the measured intensities: absorption coefficients from to cm -1 are measured on a single spectrum

CRDS measurements in Grenoble 16 quadrupole transitions were measured Line strengths equations calculation

Line strengths As derived by Balasubramanian and Narayanan [Acta Phys Hung 1994;74:341-53] based on the ideas on Watson [Can J Phys 1968;46: ] and Chiu [J Chem Phys 1965;42: ]

Line strengths equations

Quadrupole line list calculation Details of the calculations are given in Gordon et al (JQSRT 111 (2010) 1174–1183)

Inclusion of quadrupole  J = ±2 transitions

J=±2J=±2  J=0,±1  J=0,±1 and J=±2J=±2J=±2J=±2

Band Intensity and Emission Rate Integrated band intensity electric quadrupole (1.45±0.15)× cm - 1 /(molecule cm 2 ) Integrated band intensity (3.10±0.10) × cm -1 /(molecule cm 2 ) [J Chem Phys 1999;110:10749–57] Ratio ~ 215 In the A band Ratio ~ 120, 000 Einstein A-coefficient: (1.02±0.10) ×10 -6 s -1 Ab initio Einstein A-coefficient: 5 ×10 -7 s -1 [Klotz et al. Chem Phys 1984;89:223-36] If one corrects the degeneracy factors from ½ to 2/2 in theoretical calculation then the results agree very well

Lowest electronic states of O 2 b 1 Σ + a 1  g X 3 Σ g - M1, E2 E2 F 1 (J=N+S) F 2 (J=N+S-1) F 3 (J=N-S) 1.27 µm 0.76 µm g

Acknowledgements J.-F. Blavier, R. Washenfelder, P. Wennberg A. Orr-Ewing R. W. Field S. Yu NASA and ANR

Gamache RR, Goldman A. JQSRT 2001;69: