Re: Energy conversation

From: Alexander A. Vakhrushev (makaveli.lcf_at_gmail.com)
Date: Sat Dec 06 2008 - 01:23:26 CST

Thank you!

6 декабря 2008 г. 10:39 пользователь Peter Freddolino
<petefred_at_ks.uiuc.edu> написал:
> NAMD uses thermochemical calories; you should use the 4.184 J conversion.
> Best,
> Peter
>
> Alexander A. Vakhrushev wrote:
>>
>> Hi Roman, thank you for your help!
>>
>> The tricks is that I can't use NAMD as a reference for my own
>> calculations without exact value. So I also found those translations
>> for calories to Joules, but you see they are different:-) In large
>> systems they will lead to different conformations after minimization
>> process in NAMD and self implemented progs. Estimating Coulomb factor
>> and after test it seems value of 332.0636 is the correct one.
>>
>> 2008/12/6 Roman Petrenko <rpetrenko_at_gmail.com>:
>>
>>>
>>> taken from wiki page http://en.wikipedia.org/wiki/Calorie
>>>
>>> 1 cal = 4.1868 J (1 J = 0.23885 calIT) (International Steam Table
>>> calorie, 1956)
>>> 1 cal = 4.184 J (1 J = 0.23901 calth) (Thermochemical calorie)
>>> 1 cal = 4.18580 J (1 J = 0.23890 cal15) (15°C calorie)
>>>
>>> as to the factor in coulomb interactions i think you got it right, it
>>> should be around 332 if the energy is in kcal/mol units.
>>>
>>>
>>> On Fri, Dec 5, 2008 at 8:51 AM, Alexander A. Vakhrushev
>>> <makaveli.lcf_at_gmail.com> wrote:
>>>
>>>>
>>>> Hi all!
>>>>
>>>> Would you please help, what actual factor should be used to translate
>>>> NAMD's energy from "ccal*mol^-1" to "kJ*mol^-1"?
>>>> And what is the constant in Coloumb energy: U=f*q^2/r?
>>>> Is it
>>>> 00044 #define COLOUMB 332.0636
>>>> deffined in common.h?
>>>>
>>>> Thank you!
>>>>
>>>> --
>>>> Best regards,
>>>>
>>>> Dr. Alexander Vakhrushev
>>>> Institute of Applied Mechanics
>>>> Dep. of Mech. and Phys.-Chem.
>>>> of heterogeneous media
>>>> UB of Russian Academy of Sciences
>>>> 34 T. Baramzinoy St.
>>>> Izhevsk, Russia 426067
>>>>
>>>>
>>>>
>>>
>>> --
>>> Roman Petrenko.
>>> Physics Department
>>> University of Cincinnati
>>>
>>>
>>
>>
>>
>>
>

-- 
Best regards,
Dr. Alexander Vakhrushev
Institute of Applied Mechanics
Dep. of Mech. and Phys.-Chem.
of heterogeneous media
UB of Russian Academy of Sciences
34 T. Baramzinoy St.
Izhevsk, Russia 426067
----------------------------------
С уважением,
    Вахрушев Александр Александрович
к.ф.-м.н., с.н.с.
Институт прикладной механики
Уральского Отделения
Российской Академии Наук
426067, г. Ижевск
ул. Т. Барамзиной 34
+7(3412)21-45-83

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