-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 04 May 2004 01:57, Miguel wrote: > Egon wrote: > Now, we need a file which has both formalCharge and partialCharge data. > > Q: Why is it that formal charges can range from -4 to +7 but partial > charges are only in the range -1.0 to +1.0 ?
Formal charges are things made up by humans to indicate certain properties... Real atomic charges don't really exist, but are a better approximation of the real thing (the orbitals): partial atomic charges are some measure indication the electron densities (as in the electron orbitals) over the atoms... since simple models do not represent the actual orbitals (which are complex 3D objects), the densities are projected on the atom cores... far from reality, but much easier to understand and represent... And these densities can be projected onto the atomic charges in very many ways, both from quantum mechanics (orbital analysis) and from other methods... which is why the 'partial atomic charge' is a very fuzzy term... Egon - -- [EMAIL PROTECTED] PhD on Molecular Representation in Chemometrics Nijmegen University http://www.cac.sci.kun.nl/people/egonw/ GPG: 1024D/D6336BA6 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (SunOS) iD8DBQFAl0s6d9R8I9Yza6YRAvuYAKCaZe/mEWIH4bZ1haaY3DYPCMRIGgCglEnD l0j4XG1jnwPuHFrbbo/H1Iw= =yq11 -----END PGP SIGNATURE----- ------------------------------------------------------- This SF.Net email is sponsored by: Oracle 10g Get certified on the hottest thing ever to hit the market... Oracle 10g. Take an Oracle 10g class now, and we'll give you the exam FREE. http://ads.osdn.com/?ad_id149&alloc_id�66&op=click _______________________________________________ Jmol-developers mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jmol-developers
