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On 31/08/2011 2:18 AM, xiaojing gong wrote:
<blockquote
cite="mid:CAOm9RSVKp0Vm+BoKV7tJrAX=xKO53UNv8F+=AkFt2NrWdrbBtA@mail.gmail.com"
type="cite">Dear all <br>
I want to use Buckingham interactions. And I read the manual,
but I still have some questions for asking:<br>
1 ) I need to write the BN Buckingham interactions in the
format of GMX. see the following:<br>
Buckingham a(ev) b(nm) C(ev nm^6)<br>
B-B 6260 0.1  0<br>
B-N       33   0.7  0<br>
N-N       4300 0.12 0<br>
<br>
where shall I put the [defaults] lines, could I put
these in mydefined.itp file?<br>
</blockquote>
<br>
You can't put these in a molecule .itp file. These lines go in the
forcefield.itp file that is #included at the beginning of normal
.top files. There can only be one [defaults] in your whole .top,
including the #included files.<br>
<br>
<blockquote
cite="mid:CAOm9RSVKp0Vm+BoKV7tJrAX=xKO53UNv8F+=AkFt2NrWdrbBtA@mail.gmail.com"
type="cite">
<br>
[ defaults ]<br>
; nbfunc comb-rule gen-pairs fudgeLJ fudgeQQ<br>
2 1 no 1.0 1.0<br>
<br>
2) There are three parameters for Buckingham interactions,
can I write as in the following way?<br>
<br>
[ atomtypes ]<br>
;type mass charge ptype a b C6<br>
B 30.07 1.15 A    ??  ??  ??<br>
N 14.01 -1.15 A    ??   ??  ??<br>
<br>
</blockquote>
<br>
Sure. What's the alternative?<br>
<br>
<blockquote
cite="mid:CAOm9RSVKp0Vm+BoKV7tJrAX=xKO53UNv8F+=AkFt2NrWdrbBtA@mail.gmail.com"
type="cite">   3) The given Buckingham interaction parameter of
B-N may not obey any combine rules provided in GMX, what shall I
do?<br>
</blockquote>
<br>
You need to provide suitable [nonbond_params] lines. See manual
section 5.3.2<br>
<br>
Mark<br>
<br>
<blockquote
cite="mid:CAOm9RSVKp0Vm+BoKV7tJrAX=xKO53UNv8F+=AkFt2NrWdrbBtA@mail.gmail.com"
type="cite">
<br>
I will be appreciate it if you can give me some suggestions!<br>
<font color="#888888"><br>
XJ</font>
<br>
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<br>
</blockquote>
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