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 |
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!! @author Christopher Fennel |
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!! @author J. Daniel Gezelter |
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!! @version $Id: calc_sticky_pair.F90,v 1.2 2003-03-12 15:17:52 gezelter Exp $, $Date: 2003-03-12 15:17:52 $, $Name: not supported by cvs2svn $, $Revision: 1.2 $ |
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|
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 :: initialize_sticky |
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public :: do_sticky_pair |
36 |
|
37 |
contains |
38 |
|
39 |
subroutine initialize_sticky(sticky_w0, sticky_v0) |
40 |
real( kind = dp ), intent(in) :: sticky_w0, sticky_v0 |
41 |
|
42 |
! we could pass all 5 parameters if we felt like it... |
43 |
|
44 |
SSD_w0 = sticky_w0 |
45 |
SSD_v0 = sticky_v0 |
46 |
SSD_rl = 2.75_DP |
47 |
SSD_ru = 3.35_DP |
48 |
SSD_rup = 4.0_DP |
49 |
|
50 |
sticky_initialized = .true. |
51 |
return |
52 |
end subroutine initialize_sticky |
53 |
|
54 |
subroutine do_sticky_pair(atom1, atom2, d, rij, A, pot, f, t) |
55 |
|
56 |
!! This routine does only the sticky portion of the SSD potential |
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!! [Chandra and Ichiye, J. Chem. Phys. 111, 2701 (1999)]. |
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!! The Lennard-Jones and dipolar interaction must be handled separately. |
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|
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!! We assume that the rotation matrices have already been calculated |
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!! and placed in the A array. |
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|
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!! i and j are pointers to the two SSD atoms |
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|
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integer, intent(in) :: atom1, atom2 |
66 |
real (kind=dp), intent(inout) :: rij |
67 |
real (kind=dp), dimension(3), intent(in) :: d |
68 |
real (kind=dp), dimension(9,getNlocal()) :: A |
69 |
real (kind=dp), dimension(3,getNlocal()) :: f |
70 |
real (kind=dp), dimension(3,getNlocal()) :: t |
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|
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real (kind=dp) :: xi, yi, zi, xj, yj, zj, xi2, yi2, zi2, xj2, yj2, zj2 |
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real (kind=dp) :: r2, r3, r5, r6, s, sp, dsdr, dspdr |
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real (kind=dp) :: wi, wj, w, wip, wjp, wp |
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real (kind=dp) :: dwidx, dwidy, dwidz, dwjdx, dwjdy, dwjdz |
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real (kind=dp) :: dwipdx, dwipdy, dwipdz, dwjpdx, dwjpdy, dwjpdz |
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real (kind=dp) :: dwidux, dwiduy, dwiduz, dwjdux, dwjduy, dwjduz |
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real (kind=dp) :: dwipdux, dwipduy, dwipduz, dwjpdux, dwjpduy, dwjpduz |
79 |
real (kind=dp) :: zif, zis, zjf, zjs, uglyi, uglyj |
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real (kind=dp) :: drdx, drdy, drdz |
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real (kind=dp) :: txi, tyi, tzi, txj, tyj, tzj |
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real (kind=dp) :: fxii, fyii, fzii, fxjj, fyjj, fzjj |
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real (kind=dp) :: fxij, fyij, fzij, fxji, fyji, fzji |
84 |
real (kind=dp) :: fxradial, fyradial, fzradial |
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|
86 |
if (.not.sticky_initialized) then |
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write(*,*) 'Sticky forces not initialized!' |
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return |
89 |
endif |
90 |
|
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r2 = rij*rij |
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r3 = r2*rij |
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r5 = r3*r2 |
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|
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drdx = d(1) / rij |
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drdy = d(2) / rij |
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drdz = d(3) / rij |
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|
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#ifdef IS_MPI |
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! rotate the inter-particle separation into the two different |
101 |
! body-fixed coordinate systems: |
102 |
|
103 |
xi = A_row(1,atom1)*d(1) + A_row(2,atom1)*d(2) + A_row(3,atom1)*d(3) |
104 |
yi = A_row(4,atom1)*d(1) + A_row(5,atom1)*d(2) + A_row(6,atom1)*d(3) |
105 |
zi = A_row(7,atom1)*d(1) + A_row(8,atom1)*d(2) + A_row(9,atom1)*d(3) |
106 |
|
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! negative sign because this is the vector from j to i: |
108 |
|
109 |
xj = -(A_Col(1,atom2)*d(1) + A_Col(2,atom2)*d(2) + A_Col(3,atom2)*d(3)) |
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yj = -(A_Col(4,atom2)*d(1) + A_Col(5,atom2)*d(2) + A_Col(6,atom2)*d(3)) |
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zj = -(A_Col(7,atom2)*d(1) + A_Col(8,atom2)*d(2) + A_Col(9,atom2)*d(3)) |
112 |
#else |
113 |
! rotate the inter-particle separation into the two different |
114 |
! body-fixed coordinate systems: |
115 |
|
116 |
xi = a(1,atom1)*d(1) + a(2,atom1)*d(2) + a(3,atom1)*d(3) |
117 |
yi = a(4,atom1)*d(1) + a(5,atom1)*d(2) + a(6,atom1)*d(3) |
118 |
zi = a(7,atom1)*d(1) + a(8,atom1)*d(2) + a(9,atom1)*d(3) |
119 |
|
120 |
! negative sign because this is the vector from j to i: |
121 |
|
122 |
xj = -(a(1,atom2)*d(1) + a(2,atom2)*d(2) + a(3,atom2)*d(3)) |
123 |
yj = -(a(4,atom2)*d(1) + a(5,atom2)*d(2) + a(6,atom2)*d(3)) |
124 |
zj = -(a(7,atom2)*d(1) + a(8,atom2)*d(2) + a(9,atom2)*d(3)) |
125 |
#endif |
126 |
|
127 |
xi2 = xi*xi |
128 |
yi2 = yi*yi |
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zi2 = zi*zi |
130 |
|
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xj2 = xj*xj |
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yj2 = yj*yj |
133 |
zj2 = zj*zj |
134 |
|
135 |
call calc_sw_fnc(rij, s, sp, dsdr, dspdr) |
136 |
|
137 |
wi = 2.0d0*(xi2-yi2)*zi / r3 |
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wj = 2.0d0*(xj2-yj2)*zj / r3 |
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w = wi+wj |
140 |
|
141 |
zif = zi/rij - 0.6d0 |
142 |
zis = zi/rij + 0.8d0 |
143 |
|
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zjf = zj/rij - 0.6d0 |
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zjs = zj/rij + 0.8d0 |
146 |
|
147 |
wip = zif*zif*zis*zis - SSD_w0 |
148 |
wjp = zjf*zjf*zjs*zjs - SSD_w0 |
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wp = wip + wjp |
150 |
|
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#ifdef IS_MPI |
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pot_row(atom1) = pot_row(atom1) + 0.25d0*SSD_v0*(s*w + sp*wp) |
153 |
pot_col(atom2) = pot_col(atom2) + 0.25d0*SSD_v0*(s*w + sp*wp) |
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#else |
155 |
pot = pot + 0.5d0*SSD_v0*(s*w + sp*wp) |
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#endif |
157 |
|
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dwidx = 4.0d0*xi*zi/r3 - 6.0d0*xi*zi*(xi2-yi2)/r5 |
159 |
dwidy = - 4.0d0*yi*zi/r3 - 6.0d0*yi*zi*(xi2-yi2)/r5 |
160 |
dwidz = 2.0d0*(xi2-yi2)/r3 - 6.0d0*zi2*(xi2-yi2)/r5 |
161 |
|
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dwjdx = 4.0d0*xj*zj/r3 - 6.0d0*xj*zj*(xj2-yj2)/r5 |
163 |
dwjdy = - 4.0d0*yj*zj/r3 - 6.0d0*yj*zj*(xj2-yj2)/r5 |
164 |
dwjdz = 2.0d0*(xj2-yj2)/r3 - 6.0d0*zj2*(xj2-yj2)/r5 |
165 |
|
166 |
uglyi = zif*zif*zis + zif*zis*zis |
167 |
uglyj = zjf*zjf*zjs + zjf*zjs*zjs |
168 |
|
169 |
dwipdx = -2.0d0*xi*zi*uglyi/r3 |
170 |
dwipdy = -2.0d0*yi*zi*uglyi/r3 |
171 |
dwipdz = 2.0d0*(1.0d0/rij - zi2/r3)*uglyi |
172 |
|
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dwjpdx = -2.0d0*xj*zj*uglyj/r3 |
174 |
dwjpdy = -2.0d0*yj*zj*uglyj/r3 |
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dwjpdz = 2.0d0*(1.0d0/rij - zj2/r3)*uglyj |
176 |
|
177 |
dwidux = 4.0d0*(yi*zi2 + 0.5d0*yi*(xi2-yi2))/r3 |
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dwiduy = 4.0d0*(xi*zi2 - 0.5d0*xi*(xi2-yi2))/r3 |
179 |
dwiduz = - 8.0d0*xi*yi*zi/r3 |
180 |
|
181 |
dwjdux = 4.0d0*(yj*zj2 + 0.5d0*yj*(xj2-yj2))/r3 |
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dwjduy = 4.0d0*(xj*zj2 - 0.5d0*xj*(xj2-yj2))/r3 |
183 |
dwjduz = - 8.0d0*xj*yj*zj/r3 |
184 |
|
185 |
dwipdux = 2.0d0*yi*uglyi/rij |
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dwipduy = -2.0d0*xi*uglyi/rij |
187 |
dwipduz = 0.0d0 |
188 |
|
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dwjpdux = 2.0d0*yj*uglyj/rij |
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dwjpduy = -2.0d0*xj*uglyj/rij |
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dwjpduz = 0.0d0 |
192 |
|
193 |
! do the torques first since they are easy: |
194 |
! remember that these are still in the body fixed axes |
195 |
|
196 |
txi = 0.5d0*SSD_v0*(s*dwidux + sp*dwipdux) |
197 |
tyi = 0.5d0*SSD_v0*(s*dwiduy + sp*dwipduy) |
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tzi = 0.5d0*SSD_v0*(s*dwiduz + sp*dwipduz) |
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|
200 |
txj = 0.5d0*SSD_v0*(s*dwjdux + sp*dwjpdux) |
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tyj = 0.5d0*SSD_v0*(s*dwjduy + sp*dwjpduy) |
202 |
tzj = 0.5d0*SSD_v0*(s*dwjduz + sp*dwjpduz) |
203 |
|
204 |
! go back to lab frame using transpose of rotation matrix: |
205 |
|
206 |
#ifdef IS_MPI |
207 |
t_Row(1,atom1) = t_Row(1,atom1) + a_Row(1,atom1)*txi + & |
208 |
a_Row(4,atom1)*tyi + a_Row(7,atom1)*tzi |
209 |
t_Row(2,atom1) = t_Row(2,atom1) + a_Row(2,atom1)*txi + & |
210 |
a_Row(5,atom1)*tyi + a_Row(8,atom1)*tzi |
211 |
t_Row(3,atom1) = t_Row(3,atom1) + a_Row(3,atom1)*txi + & |
212 |
a_Row(6,atom1)*tyi + a_Row(9,atom1)*tzi |
213 |
|
214 |
t_Col(1,atom2) = t_Col(1,atom2) + a_Col(1,atom2)*txj + & |
215 |
a_Col(4,atom2)*tyj + a_Col(7,atom2)*tzj |
216 |
t_Col(2,atom2) = t_Col(2,atom2) + a_Col(2,atom2)*txj + & |
217 |
a_Col(5,atom2)*tyj + a_Col(8,atom2)*tzj |
218 |
t_Col(3,atom2) = t_Col(3,atom2) + a_Col(3,atom2)*txj + & |
219 |
a_Col(6,atom2)*tyj + a_Col(9,atom2)*tzj |
220 |
#else |
221 |
t(1,atom1) = t(1,atom1) + a(1,atom1)*txi + a(4,atom1)*tyi + a(7,atom1)*tzi |
222 |
t(2,atom1) = t(2,atom1) + a(2,atom1)*txi + a(5,atom1)*tyi + a(8,atom1)*tzi |
223 |
t(3,atom1) = t(3,atom1) + a(3,atom1)*txi + a(6,atom1)*tyi + a(9,atom1)*tzi |
224 |
|
225 |
t(1,atom2) = t(1,atom2) + a(1,atom2)*txj + a(4,atom2)*tyj + a(7,atom2)*tzj |
226 |
t(2,atom2) = t(2,atom2) + a(2,atom2)*txj + a(5,atom2)*tyj + a(8,atom2)*tzj |
227 |
t(3,atom2) = t(3,atom2) + a(3,atom2)*txj + a(6,atom2)*tyj + a(9,atom2)*tzj |
228 |
#endif |
229 |
! Now, on to the forces: |
230 |
|
231 |
! first rotate the i terms back into the lab frame: |
232 |
|
233 |
#ifdef IS_MPI |
234 |
fxii = a_Row(1,atom1)*(s*dwidx+sp*dwipdx) + & |
235 |
a_Row(4,atom1)*(s*dwidy+sp*dwipdy) + & |
236 |
a_Row(7,atom1)*(s*dwidz+sp*dwipdz) |
237 |
fyii = a_Row(2,atom1)*(s*dwidx+sp*dwipdx) + & |
238 |
a_Row(5,atom1)*(s*dwidy+sp*dwipdy) + & |
239 |
a_Row(8,atom1)*(s*dwidz+sp*dwipdz) |
240 |
fzii = a_Row(3,atom1)*(s*dwidx+sp*dwipdx) + & |
241 |
a_Row(6,atom1)*(s*dwidy+sp*dwipdy) + & |
242 |
a_Row(9,atom1)*(s*dwidz+sp*dwipdz) |
243 |
|
244 |
fxjj = a_Col(1,atom2)*(s*dwjdx+sp*dwjpdx) + & |
245 |
a_Col(4,atom2)*(s*dwjdy+sp*dwjpdy) + & |
246 |
a_Col(7,atom2)*(s*dwjdz+sp*dwjpdz) |
247 |
fyjj = a_Col(2,atom2)*(s*dwjdx+sp*dwjpdx) + & |
248 |
a_Col(5,atom2)*(s*dwjdy+sp*dwjpdy) + & |
249 |
a_Col(8,atom2)*(s*dwjdz+sp*dwjpdz) |
250 |
fzjj = a_Col(3,atom2)*(s*dwjdx+sp*dwjpdx)+ & |
251 |
a_Col(6,atom2)*(s*dwjdy+sp*dwjpdy) + & |
252 |
a_Col(9,atom2)*(s*dwjdz+sp*dwjpdz) |
253 |
#else |
254 |
fxii = a(1,atom1)*(s*dwidx+sp*dwipdx) + & |
255 |
a(4,atom1)*(s*dwidy+sp*dwipdy) + & |
256 |
a(7,atom1)*(s*dwidz+sp*dwipdz) |
257 |
fyii = a(2,atom1)*(s*dwidx+sp*dwipdx) + & |
258 |
a(5,atom1)*(s*dwidy+sp*dwipdy) + & |
259 |
a(8,atom1)*(s*dwidz+sp*dwipdz) |
260 |
fzii = a(3,atom1)*(s*dwidx+sp*dwipdx) + & |
261 |
a(6,atom1)*(s*dwidy+sp*dwipdy) + & |
262 |
a(9,atom1)*(s*dwidz+sp*dwipdz) |
263 |
|
264 |
fxjj = a(1,atom2)*(s*dwjdx+sp*dwjpdx) + & |
265 |
a(4,atom2)*(s*dwjdy+sp*dwjpdy) + & |
266 |
a(7,atom2)*(s*dwjdz+sp*dwjpdz) |
267 |
fyjj = a(2,atom2)*(s*dwjdx+sp*dwjpdx) + & |
268 |
a(5,atom2)*(s*dwjdy+sp*dwjpdy) + & |
269 |
a(8,atom2)*(s*dwjdz+sp*dwjpdz) |
270 |
fzjj = a(3,atom2)*(s*dwjdx+sp*dwjpdx)+ & |
271 |
a(6,atom2)*(s*dwjdy+sp*dwjpdy) + & |
272 |
a(9,atom2)*(s*dwjdz+sp*dwjpdz) |
273 |
#endif |
274 |
|
275 |
fxij = -fxii |
276 |
fyij = -fyii |
277 |
fzij = -fzii |
278 |
|
279 |
fxji = -fxjj |
280 |
fyji = -fyjj |
281 |
fzji = -fzjj |
282 |
|
283 |
! now assemble these with the radial-only terms: |
284 |
|
285 |
fxradial = 0.5d0*SSD_v0*(dsdr*drdx*w + dspdr*drdx*wp + fxii + fxji) |
286 |
fyradial = 0.5d0*SSD_v0*(dsdr*drdy*w + dspdr*drdy*wp + fyii + fyji) |
287 |
fzradial = 0.5d0*SSD_v0*(dsdr*drdz*w + dspdr*drdz*wp + fzii + fzji) |
288 |
|
289 |
#ifdef IS_MPI |
290 |
f_Row(1,atom1) = f_Row(1,atom1) + fxradial |
291 |
f_Row(2,atom1) = f_Row(2,atom1) + fyradial |
292 |
f_Row(3,atom1) = f_Row(3,atom1) + fzradial |
293 |
|
294 |
f_Col(1,atom2) = f_Col(1,atom2) + 0.5d0*SSD_v0*(-dsdr*drdx*w - & |
295 |
dspdr*drdx*wp + fxjj + fxij) |
296 |
f_Col(2,atom2) = f_Col(2,atom2) + 0.5d0*SSD_v0*(-dsdr*drdy*w - & |
297 |
dspdr*drdy*wp + fyjj + fyij) |
298 |
f_Col(3,atom2) = f_Col(3,atom2) + 0.5d0*SSD_v0*(-dsdr*drdz*w - & |
299 |
dspdr*drdz*wp + fzjj + fzij) |
300 |
#else |
301 |
f(1,atom1) = f(1,atom1) + fxradial |
302 |
f(2,atom1) = f(2,atom1) + fyradial |
303 |
f(3,atom1) = f(3,atom1) + fzradial |
304 |
|
305 |
f(1,atom2) = f(1,atom2) + 0.5d0*SSD_v0*(-dsdr*drdx*w - dspdr*drdx*wp + & |
306 |
fxjj + fxij) |
307 |
f(2,atom2) = f(2,atom2) + 0.5d0*SSD_v0*(-dsdr*drdy*w - dspdr*drdy*wp + & |
308 |
fyjj + fyij) |
309 |
f(3,atom2) = f(3,atom2) + 0.5d0*SSD_v0*(-dsdr*drdz*w - dspdr*drdz*wp + & |
310 |
fzjj + fzij) |
311 |
#endif |
312 |
|
313 |
if (doStress()) then |
314 |
tau_Temp(1) = tau_Temp(1) + fxradial * d(1) |
315 |
tau_Temp(2) = tau_Temp(2) + fxradial * d(2) |
316 |
tau_Temp(3) = tau_Temp(3) + fxradial * d(3) |
317 |
tau_Temp(4) = tau_Temp(4) + fyradial * d(1) |
318 |
tau_Temp(5) = tau_Temp(5) + fyradial * d(2) |
319 |
tau_Temp(6) = tau_Temp(6) + fyradial * d(3) |
320 |
tau_Temp(7) = tau_Temp(7) + fzradial * d(1) |
321 |
tau_Temp(8) = tau_Temp(8) + fzradial * d(2) |
322 |
tau_Temp(9) = tau_Temp(9) + fzradial * d(3) |
323 |
virial_Temp = virial_Temp + (tau_Temp(1) + tau_Temp(5) + tau_Temp(9)) |
324 |
endif |
325 |
|
326 |
end subroutine do_sticky_pair |
327 |
|
328 |
!! calculates the switching functions and their derivatives for a given |
329 |
subroutine calc_sw_fnc(r, s, sp, dsdr, dspdr) |
330 |
|
331 |
real (kind=dp), intent(in) :: r |
332 |
real (kind=dp), intent(inout) :: s, sp, dsdr, dspdr |
333 |
|
334 |
! distances must be in angstroms |
335 |
|
336 |
if (r.lt.SSD_rl) then |
337 |
s = 1.0d0 |
338 |
sp = 1.0d0 |
339 |
dsdr = 0.0d0 |
340 |
dspdr = 0.0d0 |
341 |
elseif (r.gt.SSD_rup) then |
342 |
s = 0.0d0 |
343 |
sp = 0.0d0 |
344 |
dsdr = 0.0d0 |
345 |
dspdr = 0.0d0 |
346 |
else |
347 |
sp = ((SSD_rup + 2.0d0*r - 3.0d0*SSD_rl) * (SSD_rup-r)**2) / & |
348 |
((SSD_rup - SSD_rl)**3) |
349 |
dspdr = 6.0d0*(r-SSD_rup)*(r-SSD_rl)/((SSD_rup - SSD_rl)**3) |
350 |
|
351 |
if (r.gt.SSD_ru) then |
352 |
s = 0.0d0 |
353 |
dsdr = 0.0d0 |
354 |
else |
355 |
s = ((SSD_ru + 2.0d0*r - 3.0d0*SSD_rl) * (SSD_ru-r)**2) / & |
356 |
((SSD_ru - SSD_rl)**3) |
357 |
dsdr = 6.0d0*(r-SSD_ru)*(r-SSD_rl)/((SSD_ru - SSD_rl)**3) |
358 |
endif |
359 |
endif |
360 |
|
361 |
return |
362 |
end subroutine calc_sw_fnc |
363 |
end module sticky_pair |