Dear GROMACS users, most likely I am asking a trivial question but I need to be sure about it for calculations of heat capacity based on the fluctuations of energy in canonical ensemble. I am doing simulation of water using TIP4P model. I compare two systems consisting of 216 and 8*216 = 1728 molecules. The expected fluctuations for the larger system should be reduced 8^(1/2)=2.83 times with respect to the fluctuations of the smaller system. Actually, this applies only to the fluctuations in intensive properties such as the temperature, pressure and density while the fluctuations in extensive properties such as energies exceed about 2.83 times the corresponding fluctuations for smaller system. Could you explain me the inverse ratio of fluctuations?
I have also one question regarding the heat capacity calculation. If I want to apply the formula for canonical ensemble (<E^2>-<E>^2)/(kbT^2) than the capacity should be size dependent. I am a bit puzzled about it and any explanation would be very helpful for me. Thanks in advance Zuzana.
_______________________________________________ gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read http://www.gromacs.org/mailing_lists/users.php
