//	xgear.h		header file definitions for including with xgear.c

#ifndef XGear
#define XGear

//	parameter ranges and default values

#define MAX_PARS	11			//  maximum number of parameter values + 1
#define PAR_ROWS	100			//  load parameters from file array size depth
#define PAR_COLS	51			//  load parameters from file array size width

#define PARFILE		"param.dat"		//  default parameter filename
#define RATEFILE	"rates.dat"		//  default reaction rate filename
#define SPECFILE	"specs.dat"		//  default species and initial abundances filename
#define SRCNAME		"cloud9"		//  default source or target label

#define HELPFILE	"xgearhelp.txt"		//  default help filename  
#define LSIZE		16			//  string array size for labels
#define NAMESIZE	100			//  string array size for filenames
#define PATHSIZE	250			//  string array size for pathnames

#define MIN_TEMP	5
#define MAX_TEMP	500
#define DEF_TEMP	10			//  kinetic temperature (K)

#define MIN_NH2		100
#define MAX_NH2		1000000
#define DEF_NH2		1000			//  density n(H2) (cm-3)

#define MIN_IAF		0.1
#define MAX_IAF		100
#define DEF_IAF		1			//  initial abundance factor

#define MIN_CRIF	0.1
#define MAX_CRIF	100
#define DEF_CRIF	1			//  CRI rate factor

#define MIN_UVF		0.1
#define MAX_UVF		100
#define DEF_UVF		1			//  UV field factor

#define MIN_EAV		0.5
#define MAX_EAV		25
#define DEF_EAV		5			//  extinction Av (mag)

#define ZERO_TIM	1.0e+00			//  time in years at t=0
#define MIN_TIM		1.0e+05
#define MAX_TIM		1.0e+09
#define DEF_TIM		1.0e+07			//  time in years since t=0

#define MIN_GDR		10
#define MAX_GDR		10000
#define DEF_GDR		100			//  gas to dust ratio

#define MIN_DDR		1
#define MAX_DDR		10
#define DEF_DDR		3			//  dust density ratio

#define MIN_DOS		1.0e+14
#define MAX_DOS		1.0e+16
#define DEF_DOS		7.9e+14			//  density of sites on grain surface (cm-2)

#define MIN_GRAD	1.0e-6	
#define MAX_GRAD	1.0e-4	
#define DEF_GRAD	1.0e-5			//  grain radius (cm)

#define MIN_GALB	0.1
#define MAX_GALB	0.9
#define DEF_GALB	0.6			//  dust grain albedo in far UV (for CRPHOT)

#define MIN_CRI		1.0e-18
#define MAX_CRI		1.0e-16
#define DEF_CRI		1.36e-17		//  cosmic ray ionisation (CRI) rate (s-1)

#define MIN_UV		5.0e-18
#define MAX_UV		5.0e-16
#define DEF_UV		5.0e-17			//  UV field at 1400 A (erg cm-3 A-1)

#define MIN_MODS	1	
#define MAX_MODS	100	
#define DEF_MODS	25			//  maximum number of models per run

//	other special values and reaction rates that can not be defined in rate files

#define DEF_TOL		1.0e-08			//  error control parameter

#define MIN_DRAT	1.75e-06
#define MAX_DRAT	1.75e-04
#define DEF_DRAT	1.75e-05		//  underlying D/H ratio

#define DFRAC_PARS	4			//  number of parameter values for deuterium fractionation
#define DFRAC_RK	1.7e-09			//  H3+ + HD --> H2D+ + H2 forward reaction rate
#define DFRAC_BK1	0.00981473		//  H2D+ + H2 --> H3+ + HD for the reverse reaction
#define DFRAC_BK2	1.23309			//  k includes an equilibrium constant which is T dependent
#define DFRAC_BK3	99.628			//  (Markwick et al. A&A, 376, 1054, 2001, sec. 3.2, eq. 19)

#define NPLUS_PARS	2			//  number of parameter values for N+ + H2 reaction
#define NPLUS_BK1	23.1083			//  N+ + H2 --> NH+ + H
#define NPLUS_BK2	9.1554	

//	physical constants

#define AMU 		1.660538782e-24		//  AMU atomic mass unit (g)
#define CEE		2.99792458e+8		//  speeed of light (ms-1)
#define PI		3.1415926536		//  4.0 * atan(1.0)

#endif


// end of xgear.h