The PM3 method [4] is to be used.
The PM3(tm) method is not in MOPAC, but it is so similar to PM3 that PM3(tm) calculations can be run using the EXTERNAL option. To run PM3(tm) calculations, use keywords PM3 and EXTERNAL=<filename>. The contents of the file <filename> would be the normal PM3(tm) parameters. An example of such a parameter set is as follows:
Table: Example of PM3(tm) parameter set (for Ti)
|
atnum |
22 |
|
n |
4.0 |
|
uss |
-26.45829779 |
|
upp |
-21.17197024 |
|
udd |
-36.34653108 |
|
betas |
-23.30450933 |
|
betap |
-1.07045796 |
|
betad |
-2.69874461 |
|
zs |
1.04638304 |
|
zp |
1.25955299 |
|
zd |
1.31534641 |
|
alpha |
1.57689752 |
|
gss |
12.64676054 |
|
gpp |
6.92904760 |
|
gdd |
13.01302063 |
|
gsd |
4.28866787 |
|
hsd |
1.35838275 |
|
a1 |
-0.09046372 |
|
b1 |
4.25904322 |
|
c1 |
1.25471803 |
|
a2 |
-0.01221641 |
|
b2 |
4.07610129 |
|
c2 |
2.79140274 |
|
hform |
112.30000000 |
|
zval |
4.00000000 |