/*Ne10cs123 line collision rates for lower levels of hydrogenic neon, n=1,2,3 */
#include "cddefines.h"
#include "phycon.h"

double Ne10cs123(long int i, 
  long int j)
{
	double Ne10cs123_v, 
	  TeUse, 
	  t, 
	  x;
	static double a[3]={3.346644,151.2435,71.7095};
	static double b[3]={0.5176036,20.05133,13.1543};
	static double c[3]={-0.00408072,-0.1311591,-0.1099238};
	static double d[3]={-3.064742,-129.8303,-71.0617};
	static double e[3]={-11.87587,-541.8599,-241.2520};

#	ifdef DEBUG_FUN
	fputs( "<+>Ne10cs123()\n", debug_fp );
#	endif

	/*  These are fits to Table 5 of
	 *  >>refer Aggarwal, K.M., & Kingston, A.E. 1991, PhyS, 44, 517
	 *  Ne X collision rates for 1s-3, 2s-3, and 2p-3, 
	 *  principal quantum numbers n and l.
	 *
	 *  i is the lower level and runs from 1 to 3 (1s, 2s, 2p)
	 *  j is the upper level and runs from 2 to 4 (2s, 2p, 3)
	 *  1s-2s,2p is not done here.
	 *  check temperature: fits only good between 3.8 < log Te < 6.2
	 * */
	/* arrays for fits of 3 transitions see the code below for key: */

	TeUse = MAX2(phycon.te,6310.);
	t = MIN2(TeUse,1.6e6);
	x = log10(t);

	if( i == 1 && j == 2 )
	{
		/* 1s - 2s (first entry) */
		fprintf( ioQQQ, " Neon X 2s-1s not done in Ne10cs123\n" );
		puts( "[Stop in ne10cs123]" );
		exit(1);

	}
	else if( i == 1 && j == 3 )
	{
		/* 1s - 2p (second entry) */
		fprintf( ioQQQ, " Neon X 2p-1s not done in Ne10cs123\n" );
		puts( "[Stop in ne10cs123]" );
		exit(1);

	}
	else if( i == 1 && j == 4 )
	{
		/* 1s - 3 (first entry) */
		Ne10cs123_v = a[0] + b[0]*x + c[0]*x*x*sqrt(x) + d[0]*log(x) + 
		  e[0]*log(x)/x/x;
		/*  Ne10Rate123 = cs*8.629e-6/SQRT(te)/18.
		 * */
	}
	else if( i == 2 && j == 4 )
	{
		/* 2s - 3 (second entry)         */
		Ne10cs123_v = a[1] + b[1]*x + c[1]*x*x*sqrt(x) + d[1]*log(x) + 
		  e[1]*log(x)/x/x;
		/*  Ne10Rate123 = cs*8.629e-6/SQRT(te)/18.
		 * */
	}
	else if( i == 3 && j == 4 )
	{
		/* 2p - 3s (third entry) */
		Ne10cs123_v = a[2] + b[2]*x + c[2]*x*x*sqrt(x) + d[2]*log(x) + 
		  e[2]*log(x)/x/x;
		/*  Ne10Rate123 = cs*8.629e-6/SQRT(te)/18.
		 * */
	}
	else
	{

		fprintf( ioQQQ, "  insane levels for Ne X n=1,2,3 !!!\n" );
		puts( "[Stop in ne10cs123]" );
		exit(1);

	}

#	ifdef DEBUG_FUN
	fputs( " <->Ne10cs123()\n", debug_fp );
#	endif
	return( Ne10cs123_v );
}