Jinyao Wang wrote: > Hi David, > Thank you for your help. I am very sorry to trouble you. > I have know your means that the gas-phase energy should be considered. > But I am confused that you said "the gas-phase energy (with com removed) and > add kT". > What is "the gas-phase energy (with com removed) " and Could you talk about > the details? > Better look it up in a textbook, e.g.Allen & TIldesley. The equations are also in my paper J. Phys. Chem. B. 105 pp. 2618-2626 (2001).
>>> Jinyao Wang wrote: >>>> Hi gmx-users, >>>> I want to calcualted the the vaporation enthalpy of benzaldehyde I >>>> think that the the vaporation enthalpy is the sum of non-bond >>>> interacion among the benzaldehyde molecule. So I made a NPT system >>>> simulation including 512 benzaldehyde molecule. The following is the >>>> intermolecule nonbond interaction using the g_energy. >>>> >>>> LJ-(SR)= -21128.7 Kj/mol >>>> LJ-(LR)= -889.855 Kj/mol >>>> Coulomb-(SR)= -3884.6 Kj/mol >>>> Coul.-recip = -2261.51 Kj/mol >>>> the sum of non-bond interaction = LJ-(SR) + LJ-(LR) + Coulomb-(SR) + >>>> Coul.-recip = 28164.665 Kj/mol >>>> But the experimental value of he vaporation enthalpy = 50.3 Kj/mol >>>> I have no ideal that why they have so much different. Now I don't know >>>> how to solve it. >>>> Any suggestion will be appreciated. >>>> >>> These are totals for the intermolecular energy of the system. I'm >>> guessing you didn't use "-nmol 512" to calculate these results? >> And then subtract the gas-phase energy (with com removed) and add kT. > > > Jinyao Wang > wan...@ciac.jl.cn > 2009-10-24 > > > ------------------------------------------------------------------------ > > _______________________________________________ > 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 -- David van der Spoel, Ph.D., Professor of Biology Molec. Biophys. group, Dept. of Cell & Molec. Biol., Uppsala University. Box 596, 75124 Uppsala, Sweden. Phone: +46184714205. Fax: +4618511755. sp...@xray.bmc.uu.se sp...@gromacs.org http://folding.bmc.uu.se _______________________________________________ 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