| 247 |
|
in the presence and absence of PME was applied to the previous results |
| 248 |
|
in order to predict changes to the free energy landscape. |
| 249 |
|
|
| 250 |
+ |
In addition to the above procedures, we also tested how the inclusion |
| 251 |
+ |
of the Lennard-Jones long-range correction affects the free energy |
| 252 |
+ |
results. The correction for the Lennard-Jones trucation was included |
| 253 |
+ |
by integration of the equation discussed in section |
| 254 |
+ |
\ref{sec:LJCorrections}. Rather than discuss its affect alongside the |
| 255 |
+ |
free energy results, we will just mention that while the correction |
| 256 |
+ |
does lower the free energy of the higher density states more than the |
| 257 |
+ |
lower density states, the effect is so small that it is entirely |
| 258 |
+ |
overwelmed by the error in the free energy calculation. Since its |
| 259 |
+ |
inclusion does not influence the results, the Lennard-Jones correction |
| 260 |
+ |
was omitted from all the calculations below. |
| 261 |
+ |
|
| 262 |
|
\section{Initial Free Energy Results} |
| 263 |
|
|
| 264 |
|
The calculated free energies of proton-ordered variants of three low |
| 447 |
|
\cmidrule(lr){2-6} |
| 448 |
|
& \multicolumn{5}{c}{(kcal mol$^{-1}$)} \\ |
| 449 |
|
\midrule |
| 450 |
< |
TIP5P-E & -11.98(4) & -11.96(4) & & - & -11.95(3) \\ |
| 450 |
> |
TIP5P-E & -11.98(4) & -11.96(4) & -11.87(3) & - & -11.95(3) \\ |
| 451 |
|
TIP4P-Ew & -13.11(3) & -13.09(3) & -12.97(3) & - & -12.98(3) \\ |
| 452 |
|
SPC/E & -12.99(3) & -13.00(3) & -13.03(3) & - & -12.99(3) \\ |
| 453 |
|
SSD/RF & -11.83(3) & -11.66(4) & -12.32(3) & -12.39(3) & - \\ |
| 485 |
|
higher in energy, though overlapping within error, and the less |
| 486 |
|
realistic ice B and Ice-$i^\prime$ are destabilized relative to these |
| 487 |
|
polymorphs. TIP5P-E shows similar behavior to SPC/E, where there is no |
| 488 |
< |
real free energy distinction between the various polymorphs and lend |
| 489 |
< |
credence to other results indicating the preferred form of TIP5P at |
| 490 |
< |
1~atm is a structure similar to ice B.\cite{Yamada02,Vega05,Abascal05} |
| 491 |
< |
These results indicate that TIP4P-Ew is a better mimic of real water |
| 492 |
< |
than these other models when studying crystallization and solid forms |
| 493 |
< |
of water. |
| 488 |
> |
real free energy distinction between the various polymorphs because |
| 489 |
> |
many overlap within error. While ice B is close in free energy to the |
| 490 |
> |
other polymorphs, these results fail to support the findings of other |
| 491 |
> |
researchers indicating the preferred form of TIP5P at 1~atm is a |
| 492 |
> |
structure similar to ice B.\cite{Yamada02,Vega05,Abascal05} It should |
| 493 |
> |
be noted that we are looking at TIP5P-E rather than TIP5P, and the |
| 494 |
> |
differences in the Lennard-Jones parameters could be a reason for this |
| 495 |
> |
dissimilarity. Overall, these results indicate that TIP4P-Ew is a |
| 496 |
> |
better mimic of real water than these other models when studying |
| 497 |
> |
crystallization and solid forms of water. |
| 498 |
|
|
| 499 |
|
\section{Conclusions} |
| 500 |
|
|
