Subject: RE: phase/orbitals

From: Sengen Sun <[email-masked]>
Date: Sun, 15 Jul 2001 11:23:32 -0700 (PDT)

I received 20 messages from 14 people for my postings
a month ago on this subject. No body agreed with me.
You (14 people at least) argued directly or indirectly
for no physical existence and no physical meaning of
MOs. If you are correct, what do you say about the MO
interaction control theories in pericyclic reactions?
Kinetic behaviors of physical objects can not be
controlled by something that does not exist, can they?
There are at least hundreds of publications each year
on MO controls, and there are hundreds and hundreds of
textbooks of this kind. I don’t understand the LOGIC
here. Please help me to understand the philosophy
here. Thanks.

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From: "Isaac B. Bersuker" <[email-masked]>
Date: Mon, 16 Jul 2001 13:04:02 -0500

Dear Sengen Sun:

Your question comes from the attempt to explain quantum phenomena using
classical images (I gues you are not unique in this respect). In fact, however,
quantum mechanics creates new images that are NOT understandable in classical
terms. These new images should not be "understood", they should be ACCEPTED as
such. For instance, the wave-particle dualism, the fact that any object
demonstrates properties of either waves or particles (or both) dependent on the
interaction environment, is a typical such new quantum image that has no
classical explanation. Orbitals are yet another of these examples: they are NOT
classical objects and cannot be "understood" in classical images, but they are
quite real quantum objects that manifest themselves in quite real effects
dependent on the interaction environment (like wave-particles).

Best wishes
Isaac Bersuker

Sengen Sun wrote:

> textbooks of this kind. I don▓t understand the LOGIC
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--
Dr. Isaac B. Bersuker
Institute for Theoretical Chemistry
Department of Chemistry & Biochemistry
The University of Texas at Austin
Austin, TX 78712
Phone: (512) 471-4671
Fax: (512) 471-8696
E-mail: [email-masked]

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From: Maurice Cafiero <[email-masked]>
Date: Mon, 16 Jul 2001 18:33:26 +0000

hello:
    While MO's do not exist, molecular wavefunctions do. (Although they
are not observable.) In some cases, the MO wavefunction is in fact
similar to the actual wave-function, and so have some predictive
properties. I admit I do not know about MO interaction control theories,
but I am sure that it is not something that requires the existance of
MO's. We must all keep in mind that science, even the most predictive
science, is nothing more than model-making. If we agree that quantum
mechanics is the model we currently believe to govern molecular
phenomena, then within that model is contained the fact that MO's are
nothing more than an approximation to actual wave functions (actual
within the machinery of QM).  Thus the same theory that says, " you may
use Gaussian 98 to do chemistry," also says that MO's are at best
approximations and strictly non-observable.

--
Mauricio Cafiero
Doctoral Candidate : Theoretical
                     and Computational
                     Quantum Chemistry
Department of Chemistry
University of Arizona