Dear all,<br><br> I have run an 8 ns NPT simulation of 2000 molecules of TIP3P water and I have a very low Cv value of 12.4748 J/mol K (factor = 0.000164481). The result is below. I ignored this value and have tried using formulas for Cv that I found in the two books: Allen and Tildesley & J. M. Haile but I can't come out with the right answer.<br>
Has anyone ever calculated Cv or Cp for water manually from scratch and gotten the right answer? If so, please, could you give me the details of what you did?<br><br>Statistics over 4000001 steps [ 0.0000 thru 8000.0005 ps ], 10 data sets<br>
All averages are exact over 4000001 steps<br><br>Energy Average RMSD Fluct. Drift Tot-Drift<br>------------------------------<div id=":49" class="ii gt">-------------------------------------------------<br>
Potential -79498.8 285.331 285.331 0.000110205 0.881641<br>Kinetic En. 14960.5 191.868 191.854 -0.0010135 -8.10799<br>Total Energy -64538.3 353.238 353.232 -0.000903288 -7.22631<br>
Temperature 299.962 3.84702 3.84673 -2.0321e-05 -0.162568<br>Pressure (bar) 0.945534 194.613 194.613 0.000164281 1.31425<br>Box-X 3.94528 0.00514348 0.00514348 0 0<br>
Box-Y 3.94528 0.00514348 0.00514348 0 0<br>Box-Z 3.94528 0.00514348 0.00514348 0 0<br>Volume 61.4097 0.240325 0.24032 6.42593e-07 0.00514075<br>
Density (SI) 974.3 3.80629 3.80622 -1.04747e-05 -0.0837974<br>Heat Capacity Cv: 12.4748 J/mol K (factor = 0.000164481)<br>Isothermal Compressibility: 2.27095e-05 /bar<br>Adiabatic bulk modulus: 44034.4 bar</div>
<br><br>Thank you,<br><br>Lum<br> <br>