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34 * Giving Russians Opium May Alter Current Situation
40 static char *SRCID_physics_h = "$Id$";
46 #ident "@(#) physics.h 1.6 11/23/92"
47 #endif /* HAVE_IDENT */
50 * Physical constants to be used in Gromacs.
51 * No constants (apart from 0, 1 or 2) should
52 * be anywhere else in the code.
61 #define M_PI 3.14159265358979323846
65 #define ANGSTROM (1e-10) /* Old... */
66 #define KILO (1e3) /* Thousand */
67 #define NANO (1e-9) /* A Number */
68 #define PICO (1e-12) /* A Number */
69 #define A2NM (ANGSTROM/NANO) /* NANO */
70 #define NM2A (NANO/ANGSTROM) /* 10.0 */
71 #define RAD2DEG (180.0/M_PI) /* Conversion */
72 #define DEG2RAD (M_PI/180.0) /* id */
73 #define CAL2JOULE (4.184) /* id */
74 #define E_CHARGE (1.60217733e-19) /* Coulomb */
76 #define AMU (1.6605402e-27) /* kg */
77 #define BOLTZMANN (1.380658e-23) /* (J/K) */
78 #define AVOGADRO (6.0221367e23) /* () */
79 #define RGAS (BOLTZMANN*AVOGADRO) /* (J/(mol K)) */
80 #define BOLTZ (RGAS/KILO) /* (kJ/(mol K)) */
81 #define FARADAY (E_CHARGE*AVOGADRO) /* (C/mol) */
82 #define ELECTRONVOLT (E_CHARGE*AVOGADRO/KILO) /* (kJ/mol) */
84 #define EPSILON0 (5.72765E-4) /* (e^2 Na/(kJ nm))
85 == (e^2/(kJ mol nm)) */
87 #define SPEED_OF_LIGHT (2.9979245800E05) /* nm/ps */
88 #define ATOMICMASS_keV (940000.0) /* Atomic mass in keV */
89 #define ELECTRONMASS_keV (512.0) /* Electron mas in keV */
91 #define FACEL 332.0636*CAL2JOULE /* (sqrt(ONE_4PI_EPS0)) */
92 #define ONE_4PI_EPS0 FACEL*0.1
93 #define PRESFAC (16.6054) /* bar / pressure unity */
94 #define ENM2DEBYE 48.0321 /* Convert electron nm *
96 #define DEBYE2ENM 0.02081941
97 /* to convert from a acceleration in (e V)/(amu nm) */
98 /* FIELDFAC is also Faraday's constant and E_CHARGE/(1e6 AMU) */
99 #define FIELDFAC (FARADAY/KILO)
101 #endif /* _physics_h */