c=======================================================================

      subroutine hertda(herz,v) 1
c
c     herzberg o2 absorption
c     hall,1987 private communication, based on:
c
c     ref. johnston et.al, jgr,89,11661-11665,1984
c         nicolet, 1987 (recent studies in atomic & molecular processes,
c                        plemun publishing corp, ny 1987)
c     and yoshino, et.al., 1988 (preprint of "improved absorption
c         cross sections of oxygen in the wavelength region 205-240nm
c         of the herzberg continuum")
c
      herz=0.0
      if(v.le.36000.00) return
c
c     extrapolate smoothly through the herzberg band region
c     note: herzberg bands are not correctly included
c
      corr=0.
      if(v.le.40000.)corr=((40000.-v)/4000.)*7.917e-27
c
c     conversion to atm-cm /km
c
      rlosch = 2.6868 e24 * 1.0e-5
c
c     hall's new herzberg  (least sqrs fit, ln(p))
c
c     yratio=2048.7/wl(i)  ****in angstoms****
c           =.20487/wn(i)     in microns
c           =wcm(i)/48811.0   in cm-1
c
      yratio= v    /48811.0
      herz=6.884e-24*(yratio)*exp(-69.738*(log(yratio))**2)-corr
      herz = herz * rlosch
      return
      end