This file is indexed.

/usr/share/gromacs/top/sw.itp is in gromacs-data 2018.1-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
; 
; Topology file for SW
;
; Paul van Maaren and David van der Spoel
; Molecular Dynamics Simulations of Water with Novel Shell Model Potentials
; J. Phys. Chem. B. 105 (2618-2626), 2001
;
; Force constants for the shell are given by:
;
; k = qs^2/(4 pi eps0 alpha)
; However, in the current version of the itp file and software (3.2+)
; force constants are computed in mdrun, and the input is the
; polarizability in nm^3.
;
; Some data: mu (water) = 1.8546 D ( 0.0386116 e nm)
;            1/(4 pi eps0 alpha) = 94513.94
;
; Alpha-X = 1.415   kx = 608069
; Alpha-Y = 1.528   ky = 563101
; Alpha-Z = 1.468   kz = 586116
;
; Alpha   = 1.470   k  = 585318
;
; Bonding parameters from (but without cubic term):
; D. M. Ferguson: 
; Parametrization and Evaluation of a Flexible Water Model 
; J. Comp. Chem. 16(4), 501-511 (1995)
;
; Possible defines that you can put in your topol.top:
; -DANISOTROPIC Select anisotropic polarizibility (isotropic is default).
; -DRIGID       Rigid model (flexible is default)
; -DPOSRES      Position restrain oxygen atoms
;

[ defaults ]
LJ	Geometric

[ atomtypes ]
;name        mass      charge   ptype   c6	c12
   WO    15.99940       0.0     A   	0.0	0.0
   WH     1.00800       0.0     A	0.0	0.0
   WS     0.0           0.0     S   	0.0	0.0
   WD	  0.0		0.0	D   	0.0	0.0

[ nonbond_params ]
#ifdef RIGID
#ifdef ANISOTROPIC
WH      WH      1       4.0e-5          4.0e-8
WS      WO      1       1.0e-6          1.0e-12
WS      WH      1       4.0e-5          2.766e-08
WO      WO      1       2.0e-3          1.174e-06
#else
WH      WH      1       4.0e-5          4.0e-8
WS      WO      1       1.0e-6          1.0e-12
WS      WH      1       4.0e-5          2.769e-08
WO      WO      1       2.0e-3          1.176e-06
#endif
#else
#ifdef ANISOTROPIC
WH      WH      1       4.0e-5          4.0e-8
WS      WO      1       1.0e-6          1.0e-12
WS      WH      1       4.0e-5          2.910e-08
WO      WO      1       2.0e-3          1.189e-06
#else
WH      WH      1       4.0e-5          4.0e-8
WS      WO      1       1.0e-6          1.0e-12
WS      WH      1       4.0e-5          2.937e-08
WO      WO      1       2.0e-3          1.187e-06
#endif
#endif

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; This is a the 'classical YAW' model, in which we do have the dummy.
;; The shell is attached to the dummy, in this case the gas-phase
;; quadrupole is correct. Water_pol routine can be used for this
;; model. This has four interaction sites.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[ moleculetype ]
; molname	nrexcl
SW		2

[ atoms ]
; id	at type	res nr 	residu name	at name		cg nr	charge
1	WO	1	SM2		OW1		1	1.24588
2	WH	1	SM2		HW2		1	0.62134
3	WH	1	SM2		HW3		1	0.62134
4	WD	1	SM2		DW		1 	0.0
5	WS	1	SM2		SW		1	-2.48856

#ifdef ANISOTROPIC
[ water_polarization ]
; See notes above. Alphas in nm^3 (See ref. above)
; O H H D S funct  al_x	 al_y	  al_z	   	rOH	rHH	rOD
  1 2 3 4 5 1	0.001415 0.001528 0.001468 	0.09572	0.15139 0.0137408

#else

[ polarization ]
; See notes above.	alpha (nm^3)
4	5	1 	0.00147
#endif

#ifdef RIGID
[ settles ]
; i	funct	dOH	dHH
1	1	0.09572	0.15139

#else

[ bonds ]
1	2	1   0.09572     458148.
1	3	1   0.09572     458148.

[ angles ]
; i	j	k
2	1	3    1   104.52     417.6
#endif

[ dummies3 ]
; The position of the dummies is computed as follows:
;
;		O
;  	      
;	    	D
;	  
;	H		H
;
; 2 * b = distance (OD) / [ cos (angle(DOH)) 	* distance (OH) ]
;	  0.0137408 nm	/ [ cos (104.52 / 2 deg) * 0.09572 nm	]
;         0.01557 nm 
; Dummy pos x4 = x1 + a*(x2-x1) + b*(x3-X1)
;
; Dummy from			funct	a		b
4	1	2	3	1	0.117265878	0.117265878

[ exclusions ]
; iatom excluded from interaction with i
1	2	3	4	5
2	1	3	4	5
3	1	2	4	5
4	1	2	3	5
5	1	2	3	4

#ifdef POSRES
; Restrain the oxygen...
[ position_restraints ]
; iatom type	fx	fy	fz
1	1	100	100	100
#endif