/*"oi3pcs.h" make collision strengths with electrons for 3P O I ground term.
 *>>refer Berrington, K.A. 1988, J.Phys.B, 21, 1083  for Te > 3000K
 *>>refer Bell, Berrington & Thomas 1998, MNRAS 293, L83 for 50K <= Te <= 3000K
 * numbers in cs variables refer to j value: j=0,1,2 (n=3,2,1 in 5 level atom)
 * written by Kirk Korista, 29 may 96
 * adapted by Peter van Hoof, 30 march 99 (to include Bell et al. data)
 * all data above 3000K have been adjusted down by a constant factor to make
 * them line up with Bell et al. data. */
#include "cddefines.h"
#include "tepowers.h"
#include "phycon.h"
#include "oi3pcs.h"

void oi3Pcs(double *cs21, 
	  double *cs20, 
	  double *cs10)
{
	double a, 
	  b, 
	  c, 
	  d;

#	ifdef DEBUG_FUN
	fputs( "<+>oi3Pcs()\n", debug_fp );
#	endif
	/* local variables */

	/* 3P2 - 3P1 */
	if( phycon.te <= 3.0e3 )
	{
		*cs21 = 1.49e-4*TePowers.sqrte/TePowers.te02/TePowers.te02;
	}
	else if( phycon.te <= 1.0e4 )
	{
		a = -5.5634127e-04;
		b = 8.3458102e-08;
		c = 2.3068232e-04;
		*cs21 = 0.228f*(a + b*TePowers.te32 + c*TePowers.sqrte);
	}
	else
	{
		*cs21 = 0.228*MIN2(0.222,5.563e-06*phycon.te*TePowers.te05*
		  TePowers.te02);
	}

	/* 3P2 - 3P0 */
	if( phycon.te <= 3.0e3 )
	{
		*cs20 = 4.98e-5*TePowers.sqrte;
	}
	else if( phycon.te <= 1.0e4 )
	{
		a = -3.7178028e-04;
		b = 2.0569267e-08;
		c = 1.1898539e-04;
		*cs20 = 0.288*(a + b*TePowers.te32 + c*TePowers.sqrte);
	}
	else
	{
		*cs20 = 0.288*MIN2(0.0589,1.015e-05*phycon.te/TePowers.te10/
		  TePowers.te02/TePowers.te005);
	}

	/* 3P1 - 3P0 */
	if( phycon.te <= 3.0e3 )
	{
		*cs10 = 1.83e-9*phycon.te*TePowers.te30*TePowers.te05;
	}
	else if( phycon.te <= 1.0e4 )
	{
		a = -5.9364373e-04;
		b = 0.02946867;
		c = 10768.675;
		d = 3871.9826;
		*cs10 = 0.0269*(a + b*exp(-0.5*POW2((phycon.te-c)/d)));
	}
	else
	{
		*cs10 = 0.0269*MIN2(0.074,7.794e-08*TePowers.te32/TePowers.te10/
		  TePowers.te01);
	}


#	ifdef DEBUG_FUN
	fputs( " <->oi3Pcs()\n", debug_fp );
#	endif
	return;
}