CCL: Re: CCL: Unoccupied orbitals, eigenvalues

I would criticize again the claims in the Nature paper
 rather than blame myself for not being able to resolve
 the conflicts in my mind while reading the paper.
 Even in the abstract, the authors admited orbitals to
 be mathematical constructs (human-made staff). But
 there is not such a logic that these constructs should
 be observable in the nature.
 What they really did was to knock off a trunk of
 electron density by a lazer pulse. They think this
 trunk of electron cloud to be HOMO. They then
 constructed the HOMO image mathematically in such a
 way that the the image can fit what exists already in
 their minds. I would think that this is roughly a
 reverse process to normal computations. But the goal
 of normal computations is to use physically
 meaningless orbitals as mathematical approximation to
 reach some physically meaningful quantities such as
 electron density. The reverse process is to use the
 physical quantites to construct meaningless orbitals.
 They made the image of orbitals based on their
 designed math, but they did NOT image or observe them.
 Orbitals are not observables either in the content of
 QM or in the physical reality! Therefore, their claims
 must be criticized as they confuse chemists who have
 no deep knowledge of QM. The essence of what they did
 is drawing pictures of dreamed ghosts of no physical
 reality.
 Further, they repeated several common mistakes about
 the philosophical meaning of chemistry (e.g.,"To
 observe these orbitals change as bonds are formed and
 broken is to observe the essence of chemistry").
 Chemistry is not about orbitals (or human made staff)
 but electron density and its reorganization, - the
 physical reality independant of human activities!
 Cheers for 2005!
 Sengen
 ---Original message---
 From:  Mikael Johansson <mpjohans~at~pcu.helsinki.fi>
 Date:  Mon, 20 Dec 2004 18:20:24 +0200 (EET)
 Subject:  CCL: Unoccupied orbitals, eigenvalues
 Hello All!
 Catalysed by the latest in the row of experimental
 observations of=20
 molecular orbitals (which nicely also measures the
 phase of the orbital)=20
 [1], I again started pondering on the reality of the
 _unoccupied_ MO's,=20
 this time especially between the qualitative
 difference (if any) between=20
 unoccupied orbitals with negative energies versus
 those with positive=20
 energies.
 Positive orbital energies for occupied orbitals
 indicate the=20
 non-existence of the orbital, or at least the
 inability of the chosen=20
 computational method to give a proper description of
 it (a larger, more=20
 diffuse basis set will just throw the electron,
 "orbital", away from the=20
 molecule) [2].
 Assuming for the moment that also unoccupied (virtual)
 orbitals have=20
 physical meaning, would then the ones with negative
 energies (if there=20
 are any for a give species) be "more real" than the
 ones with positive=20
 energies? I have not come across a disussion on this,
 or at least don't=20
 remember having done so.
 [1] J. Itatani et al., "Tomographic imaging of
 molecular orbitals", Nature
      432 (2004) 867-871.
 [2] I like the discussion in: N. R=F6sch, S.B.
 Trickey, J. Chem. Phys. 106
      (1997) 8940-8941.
 Merry Christmas,
      Mikael J.
      http://www.helsinki.fi/~mpjohans/
 --1824380544-1125546758-1103559624=:251477--
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