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root/group/trunk/OOPSE_old/src/mdtools/libmdCode/calc_sticky_pair.F90
Revision: 323
Committed: Wed Mar 12 15:39:01 2003 UTC (21 years, 6 months ago) by gezelter
File size: 12644 byte(s)
Log Message:
bunch of fixes

File Contents

# Content
1 !! This Module Calculates forces due to SSD potential and VDW interactions
2 !! [Chandra and Ichiye, J. Chem. Phys. 111, 2701 (1999)].
3
4 !! This module contains the Public procedures:
5
6
7 !! Corresponds to the force field defined in ssd_FF.cpp
8 !! @author Charles F. Vardeman II
9 !! @author Matthew Meineke
10 !! @author Christopher Fennel
11 !! @author J. Daniel Gezelter
12 !! @version $Id: calc_sticky_pair.F90,v 1.3 2003-03-12 15:39:01 gezelter Exp $, $Date: 2003-03-12 15:39:01 $, $Name: not supported by cvs2svn $, $Revision: 1.3 $
13
14 module sticky_pair
15
16 use simulation
17 use definitions
18 use forceGlobals
19 #ifdef IS_MPI
20 use mpiSimulation
21 #endif
22
23 implicit none
24
25 PRIVATE
26
27 logical, save :: sticky_initialized = .false.
28 real( kind = dp ), save :: SSD_w0
29 real( kind = dp ), save :: SSD_v0
30 real( kind = dp ), save :: SSD_rl
31 real( kind = dp ), save :: SSD_ru
32 real( kind = dp ), save :: SSD_rup
33
34 public :: check_sticky_FF
35 public :: set_sticky_params
36 public :: do_sticky_pair
37
38 contains
39
40 subroutine check_sticky_FF(status)
41 integer :: status = -1
42
43 if (sticky_initialized) status = 0
44 return
45 end subroutine check_sticky_FF
46
47 subroutine set_sticky_params(sticky_w0, sticky_v0)
48 real( kind = dp ), intent(in) :: sticky_w0, sticky_v0
49
50 ! we could pass all 5 parameters if we felt like it...
51
52 SSD_w0 = sticky_w0
53 SSD_v0 = sticky_v0
54 SSD_rl = 2.75_DP
55 SSD_ru = 3.35_DP
56 SSD_rup = 4.0_DP
57
58 sticky_initialized = .true.
59 return
60 end subroutine set_sticky_params
61
62 subroutine do_sticky_pair(atom1, atom2, d, rij, r2, A, pot, f, t)
63
64 !! This routine does only the sticky portion of the SSD potential
65 !! [Chandra and Ichiye, J. Chem. Phys. 111, 2701 (1999)].
66 !! The Lennard-Jones and dipolar interaction must be handled separately.
67
68 !! We assume that the rotation matrices have already been calculated
69 !! and placed in the A array.
70
71 !! i and j are pointers to the two SSD atoms
72
73 integer, intent(in) :: atom1, atom2
74 real (kind=dp), intent(inout) :: rij, r2
75 real (kind=dp), dimension(3), intent(in) :: d
76 real (kind=dp) :: pot
77 real (kind=dp), dimension(9,getNlocal()) :: A
78 real (kind=dp), dimension(3,getNlocal()) :: f
79 real (kind=dp), dimension(3,getNlocal()) :: t
80
81 real (kind=dp) :: xi, yi, zi, xj, yj, zj, xi2, yi2, zi2, xj2, yj2, zj2
82 real (kind=dp) :: r3, r5, r6, s, sp, dsdr, dspdr
83 real (kind=dp) :: wi, wj, w, wip, wjp, wp
84 real (kind=dp) :: dwidx, dwidy, dwidz, dwjdx, dwjdy, dwjdz
85 real (kind=dp) :: dwipdx, dwipdy, dwipdz, dwjpdx, dwjpdy, dwjpdz
86 real (kind=dp) :: dwidux, dwiduy, dwiduz, dwjdux, dwjduy, dwjduz
87 real (kind=dp) :: dwipdux, dwipduy, dwipduz, dwjpdux, dwjpduy, dwjpduz
88 real (kind=dp) :: zif, zis, zjf, zjs, uglyi, uglyj
89 real (kind=dp) :: drdx, drdy, drdz
90 real (kind=dp) :: txi, tyi, tzi, txj, tyj, tzj
91 real (kind=dp) :: fxii, fyii, fzii, fxjj, fyjj, fzjj
92 real (kind=dp) :: fxij, fyij, fzij, fxji, fyji, fzji
93 real (kind=dp) :: fxradial, fyradial, fzradial
94
95 if (.not.sticky_initialized) then
96 write(*,*) 'Sticky forces not initialized!'
97 return
98 endif
99
100 r3 = r2*rij
101 r5 = r3*r2
102
103 drdx = d(1) / rij
104 drdy = d(2) / rij
105 drdz = d(3) / rij
106
107 #ifdef IS_MPI
108 ! rotate the inter-particle separation into the two different
109 ! body-fixed coordinate systems:
110
111 xi = A_row(1,atom1)*d(1) + A_row(2,atom1)*d(2) + A_row(3,atom1)*d(3)
112 yi = A_row(4,atom1)*d(1) + A_row(5,atom1)*d(2) + A_row(6,atom1)*d(3)
113 zi = A_row(7,atom1)*d(1) + A_row(8,atom1)*d(2) + A_row(9,atom1)*d(3)
114
115 ! negative sign because this is the vector from j to i:
116
117 xj = -(A_Col(1,atom2)*d(1) + A_Col(2,atom2)*d(2) + A_Col(3,atom2)*d(3))
118 yj = -(A_Col(4,atom2)*d(1) + A_Col(5,atom2)*d(2) + A_Col(6,atom2)*d(3))
119 zj = -(A_Col(7,atom2)*d(1) + A_Col(8,atom2)*d(2) + A_Col(9,atom2)*d(3))
120 #else
121 ! rotate the inter-particle separation into the two different
122 ! body-fixed coordinate systems:
123
124 xi = a(1,atom1)*d(1) + a(2,atom1)*d(2) + a(3,atom1)*d(3)
125 yi = a(4,atom1)*d(1) + a(5,atom1)*d(2) + a(6,atom1)*d(3)
126 zi = a(7,atom1)*d(1) + a(8,atom1)*d(2) + a(9,atom1)*d(3)
127
128 ! negative sign because this is the vector from j to i:
129
130 xj = -(a(1,atom2)*d(1) + a(2,atom2)*d(2) + a(3,atom2)*d(3))
131 yj = -(a(4,atom2)*d(1) + a(5,atom2)*d(2) + a(6,atom2)*d(3))
132 zj = -(a(7,atom2)*d(1) + a(8,atom2)*d(2) + a(9,atom2)*d(3))
133 #endif
134
135 xi2 = xi*xi
136 yi2 = yi*yi
137 zi2 = zi*zi
138
139 xj2 = xj*xj
140 yj2 = yj*yj
141 zj2 = zj*zj
142
143 call calc_sw_fnc(rij, s, sp, dsdr, dspdr)
144
145 wi = 2.0d0*(xi2-yi2)*zi / r3
146 wj = 2.0d0*(xj2-yj2)*zj / r3
147 w = wi+wj
148
149 zif = zi/rij - 0.6d0
150 zis = zi/rij + 0.8d0
151
152 zjf = zj/rij - 0.6d0
153 zjs = zj/rij + 0.8d0
154
155 wip = zif*zif*zis*zis - SSD_w0
156 wjp = zjf*zjf*zjs*zjs - SSD_w0
157 wp = wip + wjp
158
159 #ifdef IS_MPI
160 pot_row(atom1) = pot_row(atom1) + 0.25d0*SSD_v0*(s*w + sp*wp)
161 pot_col(atom2) = pot_col(atom2) + 0.25d0*SSD_v0*(s*w + sp*wp)
162 #else
163 pot = pot + 0.5d0*SSD_v0*(s*w + sp*wp)
164 #endif
165
166 dwidx = 4.0d0*xi*zi/r3 - 6.0d0*xi*zi*(xi2-yi2)/r5
167 dwidy = - 4.0d0*yi*zi/r3 - 6.0d0*yi*zi*(xi2-yi2)/r5
168 dwidz = 2.0d0*(xi2-yi2)/r3 - 6.0d0*zi2*(xi2-yi2)/r5
169
170 dwjdx = 4.0d0*xj*zj/r3 - 6.0d0*xj*zj*(xj2-yj2)/r5
171 dwjdy = - 4.0d0*yj*zj/r3 - 6.0d0*yj*zj*(xj2-yj2)/r5
172 dwjdz = 2.0d0*(xj2-yj2)/r3 - 6.0d0*zj2*(xj2-yj2)/r5
173
174 uglyi = zif*zif*zis + zif*zis*zis
175 uglyj = zjf*zjf*zjs + zjf*zjs*zjs
176
177 dwipdx = -2.0d0*xi*zi*uglyi/r3
178 dwipdy = -2.0d0*yi*zi*uglyi/r3
179 dwipdz = 2.0d0*(1.0d0/rij - zi2/r3)*uglyi
180
181 dwjpdx = -2.0d0*xj*zj*uglyj/r3
182 dwjpdy = -2.0d0*yj*zj*uglyj/r3
183 dwjpdz = 2.0d0*(1.0d0/rij - zj2/r3)*uglyj
184
185 dwidux = 4.0d0*(yi*zi2 + 0.5d0*yi*(xi2-yi2))/r3
186 dwiduy = 4.0d0*(xi*zi2 - 0.5d0*xi*(xi2-yi2))/r3
187 dwiduz = - 8.0d0*xi*yi*zi/r3
188
189 dwjdux = 4.0d0*(yj*zj2 + 0.5d0*yj*(xj2-yj2))/r3
190 dwjduy = 4.0d0*(xj*zj2 - 0.5d0*xj*(xj2-yj2))/r3
191 dwjduz = - 8.0d0*xj*yj*zj/r3
192
193 dwipdux = 2.0d0*yi*uglyi/rij
194 dwipduy = -2.0d0*xi*uglyi/rij
195 dwipduz = 0.0d0
196
197 dwjpdux = 2.0d0*yj*uglyj/rij
198 dwjpduy = -2.0d0*xj*uglyj/rij
199 dwjpduz = 0.0d0
200
201 ! do the torques first since they are easy:
202 ! remember that these are still in the body fixed axes
203
204 txi = 0.5d0*SSD_v0*(s*dwidux + sp*dwipdux)
205 tyi = 0.5d0*SSD_v0*(s*dwiduy + sp*dwipduy)
206 tzi = 0.5d0*SSD_v0*(s*dwiduz + sp*dwipduz)
207
208 txj = 0.5d0*SSD_v0*(s*dwjdux + sp*dwjpdux)
209 tyj = 0.5d0*SSD_v0*(s*dwjduy + sp*dwjpduy)
210 tzj = 0.5d0*SSD_v0*(s*dwjduz + sp*dwjpduz)
211
212 ! go back to lab frame using transpose of rotation matrix:
213
214 #ifdef IS_MPI
215 t_Row(1,atom1) = t_Row(1,atom1) + a_Row(1,atom1)*txi + &
216 a_Row(4,atom1)*tyi + a_Row(7,atom1)*tzi
217 t_Row(2,atom1) = t_Row(2,atom1) + a_Row(2,atom1)*txi + &
218 a_Row(5,atom1)*tyi + a_Row(8,atom1)*tzi
219 t_Row(3,atom1) = t_Row(3,atom1) + a_Row(3,atom1)*txi + &
220 a_Row(6,atom1)*tyi + a_Row(9,atom1)*tzi
221
222 t_Col(1,atom2) = t_Col(1,atom2) + a_Col(1,atom2)*txj + &
223 a_Col(4,atom2)*tyj + a_Col(7,atom2)*tzj
224 t_Col(2,atom2) = t_Col(2,atom2) + a_Col(2,atom2)*txj + &
225 a_Col(5,atom2)*tyj + a_Col(8,atom2)*tzj
226 t_Col(3,atom2) = t_Col(3,atom2) + a_Col(3,atom2)*txj + &
227 a_Col(6,atom2)*tyj + a_Col(9,atom2)*tzj
228 #else
229 t(1,atom1) = t(1,atom1) + a(1,atom1)*txi + a(4,atom1)*tyi + a(7,atom1)*tzi
230 t(2,atom1) = t(2,atom1) + a(2,atom1)*txi + a(5,atom1)*tyi + a(8,atom1)*tzi
231 t(3,atom1) = t(3,atom1) + a(3,atom1)*txi + a(6,atom1)*tyi + a(9,atom1)*tzi
232
233 t(1,atom2) = t(1,atom2) + a(1,atom2)*txj + a(4,atom2)*tyj + a(7,atom2)*tzj
234 t(2,atom2) = t(2,atom2) + a(2,atom2)*txj + a(5,atom2)*tyj + a(8,atom2)*tzj
235 t(3,atom2) = t(3,atom2) + a(3,atom2)*txj + a(6,atom2)*tyj + a(9,atom2)*tzj
236 #endif
237 ! Now, on to the forces:
238
239 ! first rotate the i terms back into the lab frame:
240
241 #ifdef IS_MPI
242 fxii = a_Row(1,atom1)*(s*dwidx+sp*dwipdx) + &
243 a_Row(4,atom1)*(s*dwidy+sp*dwipdy) + &
244 a_Row(7,atom1)*(s*dwidz+sp*dwipdz)
245 fyii = a_Row(2,atom1)*(s*dwidx+sp*dwipdx) + &
246 a_Row(5,atom1)*(s*dwidy+sp*dwipdy) + &
247 a_Row(8,atom1)*(s*dwidz+sp*dwipdz)
248 fzii = a_Row(3,atom1)*(s*dwidx+sp*dwipdx) + &
249 a_Row(6,atom1)*(s*dwidy+sp*dwipdy) + &
250 a_Row(9,atom1)*(s*dwidz+sp*dwipdz)
251
252 fxjj = a_Col(1,atom2)*(s*dwjdx+sp*dwjpdx) + &
253 a_Col(4,atom2)*(s*dwjdy+sp*dwjpdy) + &
254 a_Col(7,atom2)*(s*dwjdz+sp*dwjpdz)
255 fyjj = a_Col(2,atom2)*(s*dwjdx+sp*dwjpdx) + &
256 a_Col(5,atom2)*(s*dwjdy+sp*dwjpdy) + &
257 a_Col(8,atom2)*(s*dwjdz+sp*dwjpdz)
258 fzjj = a_Col(3,atom2)*(s*dwjdx+sp*dwjpdx)+ &
259 a_Col(6,atom2)*(s*dwjdy+sp*dwjpdy) + &
260 a_Col(9,atom2)*(s*dwjdz+sp*dwjpdz)
261 #else
262 fxii = a(1,atom1)*(s*dwidx+sp*dwipdx) + &
263 a(4,atom1)*(s*dwidy+sp*dwipdy) + &
264 a(7,atom1)*(s*dwidz+sp*dwipdz)
265 fyii = a(2,atom1)*(s*dwidx+sp*dwipdx) + &
266 a(5,atom1)*(s*dwidy+sp*dwipdy) + &
267 a(8,atom1)*(s*dwidz+sp*dwipdz)
268 fzii = a(3,atom1)*(s*dwidx+sp*dwipdx) + &
269 a(6,atom1)*(s*dwidy+sp*dwipdy) + &
270 a(9,atom1)*(s*dwidz+sp*dwipdz)
271
272 fxjj = a(1,atom2)*(s*dwjdx+sp*dwjpdx) + &
273 a(4,atom2)*(s*dwjdy+sp*dwjpdy) + &
274 a(7,atom2)*(s*dwjdz+sp*dwjpdz)
275 fyjj = a(2,atom2)*(s*dwjdx+sp*dwjpdx) + &
276 a(5,atom2)*(s*dwjdy+sp*dwjpdy) + &
277 a(8,atom2)*(s*dwjdz+sp*dwjpdz)
278 fzjj = a(3,atom2)*(s*dwjdx+sp*dwjpdx)+ &
279 a(6,atom2)*(s*dwjdy+sp*dwjpdy) + &
280 a(9,atom2)*(s*dwjdz+sp*dwjpdz)
281 #endif
282
283 fxij = -fxii
284 fyij = -fyii
285 fzij = -fzii
286
287 fxji = -fxjj
288 fyji = -fyjj
289 fzji = -fzjj
290
291 ! now assemble these with the radial-only terms:
292
293 fxradial = 0.5d0*SSD_v0*(dsdr*drdx*w + dspdr*drdx*wp + fxii + fxji)
294 fyradial = 0.5d0*SSD_v0*(dsdr*drdy*w + dspdr*drdy*wp + fyii + fyji)
295 fzradial = 0.5d0*SSD_v0*(dsdr*drdz*w + dspdr*drdz*wp + fzii + fzji)
296
297 #ifdef IS_MPI
298 f_Row(1,atom1) = f_Row(1,atom1) + fxradial
299 f_Row(2,atom1) = f_Row(2,atom1) + fyradial
300 f_Row(3,atom1) = f_Row(3,atom1) + fzradial
301
302 f_Col(1,atom2) = f_Col(1,atom2) + 0.5d0*SSD_v0*(-dsdr*drdx*w - &
303 dspdr*drdx*wp + fxjj + fxij)
304 f_Col(2,atom2) = f_Col(2,atom2) + 0.5d0*SSD_v0*(-dsdr*drdy*w - &
305 dspdr*drdy*wp + fyjj + fyij)
306 f_Col(3,atom2) = f_Col(3,atom2) + 0.5d0*SSD_v0*(-dsdr*drdz*w - &
307 dspdr*drdz*wp + fzjj + fzij)
308 #else
309 f(1,atom1) = f(1,atom1) + fxradial
310 f(2,atom1) = f(2,atom1) + fyradial
311 f(3,atom1) = f(3,atom1) + fzradial
312
313 f(1,atom2) = f(1,atom2) + 0.5d0*SSD_v0*(-dsdr*drdx*w - dspdr*drdx*wp + &
314 fxjj + fxij)
315 f(2,atom2) = f(2,atom2) + 0.5d0*SSD_v0*(-dsdr*drdy*w - dspdr*drdy*wp + &
316 fyjj + fyij)
317 f(3,atom2) = f(3,atom2) + 0.5d0*SSD_v0*(-dsdr*drdz*w - dspdr*drdz*wp + &
318 fzjj + fzij)
319 #endif
320
321 if (doStress()) then
322 tau_Temp(1) = tau_Temp(1) + fxradial * d(1)
323 tau_Temp(2) = tau_Temp(2) + fxradial * d(2)
324 tau_Temp(3) = tau_Temp(3) + fxradial * d(3)
325 tau_Temp(4) = tau_Temp(4) + fyradial * d(1)
326 tau_Temp(5) = tau_Temp(5) + fyradial * d(2)
327 tau_Temp(6) = tau_Temp(6) + fyradial * d(3)
328 tau_Temp(7) = tau_Temp(7) + fzradial * d(1)
329 tau_Temp(8) = tau_Temp(8) + fzradial * d(2)
330 tau_Temp(9) = tau_Temp(9) + fzradial * d(3)
331 virial_Temp = virial_Temp + (tau_Temp(1) + tau_Temp(5) + tau_Temp(9))
332 endif
333
334 end subroutine do_sticky_pair
335
336 !! calculates the switching functions and their derivatives for a given
337 subroutine calc_sw_fnc(r, s, sp, dsdr, dspdr)
338
339 real (kind=dp), intent(in) :: r
340 real (kind=dp), intent(inout) :: s, sp, dsdr, dspdr
341
342 ! distances must be in angstroms
343
344 if (r.lt.SSD_rl) then
345 s = 1.0d0
346 sp = 1.0d0
347 dsdr = 0.0d0
348 dspdr = 0.0d0
349 elseif (r.gt.SSD_rup) then
350 s = 0.0d0
351 sp = 0.0d0
352 dsdr = 0.0d0
353 dspdr = 0.0d0
354 else
355 sp = ((SSD_rup + 2.0d0*r - 3.0d0*SSD_rl) * (SSD_rup-r)**2) / &
356 ((SSD_rup - SSD_rl)**3)
357 dspdr = 6.0d0*(r-SSD_rup)*(r-SSD_rl)/((SSD_rup - SSD_rl)**3)
358
359 if (r.gt.SSD_ru) then
360 s = 0.0d0
361 dsdr = 0.0d0
362 else
363 s = ((SSD_ru + 2.0d0*r - 3.0d0*SSD_rl) * (SSD_ru-r)**2) / &
364 ((SSD_ru - SSD_rl)**3)
365 dsdr = 6.0d0*(r-SSD_ru)*(r-SSD_rl)/((SSD_ru - SSD_rl)**3)
366 endif
367 endif
368
369 return
370 end subroutine calc_sw_fnc
371 end module sticky_pair