#### /matlab/getq.m

Objective C | 50 lines | 39 code | 11 blank | 0 comment | 2 complexity | c8d0c5196c5eebccf7189e549b3ababc MD5 | raw file

1function k_q = getq(tint,wmr) 2% getq.m Get quenching rate as function of internal temperature 3% and water mixing ratio supplied in wmr (mole fraction). 4% getq takes as input the internal temperature 'tint' and returns 5% the OH fluorescence quenching rate from an 80/20 mixture of N2 6% and O2. The coefficients a, b, c were derived from data supplied 7% by Heard (Faraday Trans., V93, 1997 for O2 and N2; private comm. 8% for H2O.) 9% 10% quenching cross-sections were approximated linearly, of the form 11% sigma = -mT + n T in Kelvins 12% 13% k_q(T) = sigma(T) * <v> 14% 15% <v> is the average thermal collision velocity [8RT/(pi*mu)]^1/2, 16% where mu is the reduced mass of the collision. 17% 18% the individual quenching rates have the form 19% k = aT^(1/2) - bT^(3/2) + c 20% revised by I. Faloona (12/97) 21% H2O coefficients revised by MM (1/02) according to [Bailey et al., Chem. Phys. Lett., 1999] 22 23kB = 1.381e-19; 24 25% N2 26 27an2 = -1.668e-11; 28bn2 = -1.731e-14; 29cn2 = 2.313e-10; 30 31% O2 32 33ao2 = 1.008e-11; 34bo2 = 1.655e-14; 35co2 = 5.129e-11; 36 37% H20 38 39ah2o = -4.017e-10; 40bh2o = -4.4686e-13; 41ch2o = 5.3137e-09; 42 43% calculate quenching rate constants 44 45kn2 = an2*tint.^(0.5) - bn2*tint.^(1.5) + cn2; 46ko2 = ao2*tint.^(0.5) - bo2*tint.^(1.5) + co2; 47kh2o = ah2o*tint.^(0.5) - bh2o*tint.^(1.5) + ch2o; 48 49 50k_q = ((1-wmr).* (0.791*kn2 + 0.209*ko2) + wmr.*kh2o)./(kB*tint);