CCL:G: Fukui functions

 Sent to CCL by: Sengen Sun [sengensun..yahoo.com]
 I slightly disgree with Nuno.   Mulliken charges do
 have some advantages over other indices. They are
 mathematical indicators of charge distributions,
 rough, but easy and convenient to use. As they are
 correlated with meaningful physical reality, they can
 be easily understood. Of cource, we should be cautious
 of their accuracy, and I may avoid them especially
 when difsusion function is used.
 As pointed by Dr James Robinson
 http://www.ccl.net/cgi-bin/ccl/message-new?2006+01+14+004
 "a calculation to simply disprove/support an idea is
 adequate" no matter what you use. The criterion is
 whether your results make a sense. I don't think it is
 the time to trash all "low level" calculations or
 parameters.
 The reason for me to respond to this thread is that I
 made a very important discovery about the mechanism of
 concerted cycloadditions based on Mulliken charges. I
 tried hard but could not make it published anywhere as
 every referee had his/her own opinions what I should
 use. But in my opinion, none of their suggestions
 could lead to an easy and true understanding of the
 mechanism. My computational results make a sense and I
 am available to defend my mechanistic theory anywhere
 and any time. Again, this is about my Preprint papers
 posted in the Internet 5 years ago, which are
 available to CCLers upon request by e-mail.
 In contrast, Fukui function indices are very hard to
 be understood in particular situations (not as easy as
 when they are initially defined under idealized
 situations). They are essentially related to the FMOs,
 but the FMOs often failed in representing the physical
 effect of the overall electron density.
 A good example to explain this may be the work by
 Nguyen et al. (JPC 2001, 105, 10943, and 2004, 108,
 9169), who made evidently wrong conclusions in many of
 their papers about the mechanism of dipolar
 cycloadditions based on Fukui indices. One of their
 examples is the reaction between fulminic acid and
 acetylene. A true organic chemist would immediately
 recognize that fulminic acid accepts electron from its
 carbon and donates electron from its oxygen, simply
 because there are electron accepting and donating
 forces. Nguyen et al made some very sophistigated
 analyses of Fukui indices and made the opposite
 conclusion - fulminic acid oxygen accepts electron and
 carbon donates electron. When I first read their
 papers about 7 years ago, I was absolutely astonished
 by the evident conceptual mistakes derived from FMO
 indices.
 Sengen
 > From: "Nuno A. G. Bandeira"
 > <nuno.bandeira.:.ist.utl.pt>
 > Subject: CCL:G: Fukui functions
 > Date: Thu, 09 Feb 2006 18:08:17 +0000
 >
 >
 --------------------------------------------------------------------------------
 >
 > Godefroid Gahungu ggahungu##yahoo.fr wrote:
 >
 > I am attempting a calculation of the condensed
 > Fuikui
 > functions and to my knowledge, these can be
 > calculated
 > using the simple procedure (based on. Mulliken
 > population analysis) given by Yang and Mortier [W.
 > Yang, W. J. Mortier, J. Am. Chem. Soc. 1986, 108,
 > 5708-5711]. It seems that for a system of N
 > electrons,
 > independent calculations are to be made for
 > corresponding N-1, N, and N+1 electron systems with
 > the same molecular geometry. Mulliken population
 > analysis should yield (gross charges) qk(N-1),
 > qk(N),and qk(N + 1) for all atoms k which are to be
 > used in these calculations.
 >           So, could anyone provide me with some
 > details (from the preparation of
 >  the Gaussian input file to the extraction of the
 > necessary data from the output)
 >  to be executed in order to do this!!!
 >
 >
 > Arguslab (www.planaria-software.com) can
 > automatically
 > make you an input file for Gaussian. I wouldn't
 > trust
 > Mulliken charges if I were you. It's better that you
 > use NPA or Hirshfeld charges.
 >  cheers,
 >  --
 >  Nuno A. G. Bandeira, AMRSC
 >  Graduate researcher and molecular sculptor
 >  Inorganic and Theoretical Chemistry Group,
 >  Faculty of Science
 >  University of Lisbon - C8 building, Campo Grande,
 >  1749-016 Lisbon,Portugal
 >  http://cqb.fc.ul.pt/intheochem/nuno.html
 >  Doctoral student  .  IST,Lisbon
 >
 >
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