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?
>> >> 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