Subject: ZINDO with point charges summary

From: Lorant Janosi <lj8q5)at(mizzou.edu>
Date: Fri, 12 Dec 2003 21:37:16 -0600

Dear CCL,

Here is a summary of responses regarding my question:

Dear CCL's,

I would like to do some ZINDO calculations on a system that has point 
charges included. Does anyone know a software that does that, because I 
know gaussian 98/03 cannot do this (I tried & does not work; g03 is 
specifiying that this is not possible, too).
Or, how could I do some other semiempirical calculations of excited 
states on a system with point charges?

Thanks a lot.
Lori.

RESPONSES:
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Dear Lorant,

You can do it in HyperChem. First, you place hydrogens where you want to place charges, then you select them (one by one) and set a formal charge you need (it can be any positive or negative number). Then you deselect them and select your molecular system. Then you start the calculation! As far as I know, these hydrogen are not included in the calculation (as hydrogens) if they are not selected. Instead, they are included as point charges.

Best regards,
Igor.

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I'm not sure these are the same thing, but MOPAC has a "particle" called 
a "sparkle", which is a massless, orbital-less point of pure charge. 
They can be used inter alia as counterions or to create a shaped, 
charged field. I haven't worked with excited states very much in MOPAC, 
but I know of no reason why these could not be used (they are considered 
part of the molecule). If this is what you have in mind, check the MOPAC 
manual (version 6 is my favorite, and the best documented) for 
additional information, or get back to me.

Cheers,
Steve
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Dear Lori,
 
My software package 'QuChem' can do calculation for any multiplicity 
states ( except excited singlet - it was not necessary for me) with 
array of point charges.
 
Best wishes
Dr. Vladimir Khavryutchenko
e-mail: vkhavr)at(compchem.kiev.ua <mailto:vkhavr)at(compchem.kiev.ua>
05 Dec. 2003

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Thanks to you all,
Lori.