;+
; NAME:
;  lellouch94co
; PURPOSE: (one line)
;  radiative cooling rate (Q) from Yelle and Lunine 1989 FOR 7.7 um
; CALLING SEQUENCE:
;  lellouch94co, t,n,mixrat, h, p10=p10, distau=distau
; INPUTS:
; KEYWORD INPUT PARAMETERS
;  p10 - probability that a V-T transition occurs during a collision
; OUTPUTS:
;  h - heading rate (erg/cm^3/s)
;  dh - temperature derivative dH/dt (erg/cm^3/s/K)
; MODIFICATION HISTORY:
;  Written 2004 Apr, by Leslie Young, SwRI
;  2006 Dec 26 LAY added dlco
;-
pro lellouch94co, t, n, mixrat, lco, dlco, p10=p10, distau=distau

if not keyword_set(p10) then p10 = 1e-6
if not keyword_set(distau) then distau=30.121473

;print, 'LELLOUCH'

    physconstants
    
; set up constants

    fn = !spectralib.by_molecdir+'05_HIT96.PAR
    lna = rd_band(fn, 5, 1, 1, 1)
    nu_hz = !phys.c * lna.nu0

    nt = n_elements(t)
    
    lco = fltarr(nt)
    for i = 0, nt-1 do begin
        changept_specline_array, lns, 10, t[i]
        bnu = planck_nu(t[i], nu_hz)
        s = lna.s * !phys.c
        lco[i] = 4. * !pi * n[i] * mixrat * total(bnu * s)
    end

    if n_params() eq 5 then begin
        dt = 0.01 * t
        dlco = fltarr(nt)
        for i = 0, nt-1 do begin
            t2 = t[i] + dt[i]
            n2 = n * t[i]/t2
            changept_specline_array, lns, 10, t2
            bnu = planck_nu(t2, nu_hz)
            s = lna.s * !phys.c
            dlco[i] = (4. * !pi * n2 * mixrat * total(bnu * s) - lco[i])/dt[i]
        end
    end

end