Subject: Some question in using Tinker

From: "T,>2" <yuanjingnk$at$nankai.edu.cn>
Date: Wed, 12 Nov 2003 21:36:43 +0800

Dear Sir or madam:

I meet some difficulties in making a chloroform (CHCl3) box in NPT conditions
byusing tinker. In NPT simulation(300K,1atm),the density is about 1.30g/ml,which
is smaller than experimental data(1.48g/ml), and the delta H(vap) didn't agree to
experimental data. Could you give me some advice on how to make the box more
reseanable?I want to use  "rattle bonds" keyword to control the bond length as
1.758A, however, there is errors as "constrain not satisfatied".Could you tell me
where is wrong ?

My tinker.key file is:
forcefield              OPLS United-ATOM
vdwtype                 LENNARD-JONES
radiusrule              GEOMETRIC
radiustype              SIGMA
radiussize              DIAMETER
epsilonrule             GEOMETRIC
torsionunit             0.5
vdw-14-scale            0.5
chg-14-scale            0.5
dielectric              1.0
a-axis       30.00
cut-off      14.00
TAU-TEMPERATURE 0.1
rattle       bonds
integrate    verlet
atom      1    CH      "CHCl3 CH      "       7      13.018     3
atom      2    Cl      "CHCl3 CH      "      17      35.453     1
vdw          1                 3.8000     0.0800
vdw          2                 3.4700     0.3000
bond         1    2            245.0      1.7580
angle        1    2    3        78.00     110.30
charge       1                0.4200
charge       2               -0.1400

YuanJing
Nankai University P.R.China
E-mail:yuanjingnk$at$nankai.edu.cn