| 299 |
|
TIP3P & -11.41(2) & -11.23(3) & -11.82(3) & -12.30(3)\\ |
| 300 |
|
TIP4P & -11.84(3) & -12.04(2) & -12.08(3) & -12.33(3)\\ |
| 301 |
|
TIP5P & -11.85(3) & -11.86(2) & -11.96(2) & -12.29(2)\\ |
| 302 |
< |
SPC/E & -12.67(2) & -12.96(2) & -13.25(3) & -13.55(2)\\ |
| 302 |
> |
SPC/E & -12.87(2) & -13.05(2) & -13.26(3) & -13.55(2)\\ |
| 303 |
|
SSD/E & -11.27(2) & -11.19(4) & -12.09(2) & -12.54(2)\\ |
| 304 |
|
SSD/RF & -11.51(2) & -11.47(2) & -12.08(3) & -12.29(2)\\ |
| 305 |
|
\end{tabular} |
| 432 |
|
To further study the changes resulting to the inclusion of a |
| 433 |
|
long-range interaction correction, the effect of an Ewald summation |
| 434 |
|
was estimated by applying the potential energy difference do to its |
| 435 |
< |
inclusion in systems in the presence and absence of the |
| 436 |
< |
correction. This was accomplished by calculation of the potential |
| 437 |
< |
energy of identical crystals both with and without PME. The free |
| 438 |
< |
energies for the investigated polymorphs using the TIP3P and SPC/E |
| 439 |
< |
water models are shown in Table \ref{pmeShift}. The same trend pointed |
| 440 |
< |
out through increase of cutoff radius is observed in these PME |
| 441 |
< |
results. Ice-{\it i} is the preferred polymorph at ambient conditions |
| 442 |
< |
for both the TIP3P and SPC/E water models; however, the narrowing of |
| 443 |
< |
the free energy differences between the various solid forms is |
| 435 |
> |
inclusion in systems in the presence and absence of the correction. |
| 436 |
> |
This was accomplished by calculation of the potential energy of |
| 437 |
> |
identical crystals both with and without PME. The free energies for |
| 438 |
> |
the investigated polymorphs using the TIP3P and SPC/E water models are |
| 439 |
> |
shown in Table \ref{pmeShift}. The same trend pointed out through |
| 440 |
> |
increase of cutoff radius is observed in these PME results. Ice-{\it |
| 441 |
> |
i} is the preferred polymorph at ambient conditions for both the TIP3P |
| 442 |
> |
and SPC/E water models; however, the narrowing of the free energy |
| 443 |
> |
differences between the various solid forms with the SPC/E model is |
| 444 |
|
significant enough that it becomes less clear that it is the most |
| 445 |
< |
stable polymorph with the SPC/E model. The free energies of Ice-{\it |
| 446 |
< |
i} and ice B nearly overlap within error, with ice $I_c$ just outside |
| 447 |
< |
as well, indicating that Ice-{\it i} might be metastable with respect |
| 448 |
< |
to ice B and possibly ice $I_c$ with SPC/E. However, these results do |
| 449 |
< |
not significantly alter the finding that the Ice-{\it i} polymorph is |
| 450 |
< |
a stable crystal structure that should be considered when studying the |
| 445 |
> |
stable polymorph. The free energies of Ice-{\it i} and $I_\textrm{c}$ |
| 446 |
> |
overlap within error, while ice B and $I_\textrm{h}$ are just outside |
| 447 |
> |
at t slightly higher free energy. This indicates that with SPC/E, |
| 448 |
> |
Ice-{\it i} might be metastable with all the studied polymorphs, |
| 449 |
> |
particularly ice $I_\textrm{c}$. However, these results do not |
| 450 |
> |
significantly alter the finding that the Ice-{\it i} polymorph is a |
| 451 |
> |
stable crystal structure that should be considered when studying the |
| 452 |
|
phase behavior of water models. |
| 453 |
|
|
| 454 |
|
\begin{table*} |
| 464 |
|
Water Model & $I_h$ & $I_c$ & B & Ice-{\it i} \\ |
| 465 |
|
\hline |
| 466 |
|
TIP3P & -11.53(2) & -11.24(3) & -11.51(3) & -11.67(3) \\ |
| 467 |
< |
SPC/E & -12.77(2) & -12.92(2) & -12.96(3) & -13.02(2) \\ |
| 467 |
> |
SPC/E & -12.97(2) & -13.00(2) & -12.96(3) & -13.02(2) \\ |
| 468 |
|
\end{tabular} |
| 469 |
|
\label{pmeShift} |
| 470 |
|
\end{center} |
