Št. zadetkov: 77
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
After pointing out several discrepancies between electron difference density results and Lewis bonding theory, the course proceeds to quantum mechanics in search of a fundamental understanding of chemical bonding. The wave function ψ, which beginning students find confusing, was equally confusing to ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride expands on the recently introduced concept of the wave function by illustrating the relationship of the magnitude of the curvature of the wave function to the kinetic energy of the system, as well as the relationship of the square of the wave function to the electron probability de ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
After showing how a double-minimum potential generates one-dimensional bonding, Professor McBride moves on to multi-dimensional wave functions. Solving Schrödinger's three-dimensional differential equation might have been daunting, but it was not, because the necessary formulas had been worked out m ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
In discussions of the Schrödinger equation thus far, the systems described were either one-dimensional or involved a single electron. After discussing how increased nuclear charge affects the energies of one-electron atoms and then discussing hybridization, this lecture finally addresses the simple ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
The lecture opens with tricks ("Z-effective" and "Self Consistent Field") that allow one to correct approximately for the error in using orbitals that is due to electron repulsion. This error is hidden by naming it "correlation energy." Professor McBride introduces molecules by modifying J.J. Thomso ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
This lecture begins by applying the united-atom "plum-pudding" view of molecular orbitals, introduced in the previous lecture, to more complex molecules. It then introduces the more utilitarian concept of localized pairwise bonding between atoms. Formulating an atom-pair molecular orbital as the sum ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride uses this lecture to show that covalent bonding depends primarily on two factors: orbital overlap and energy-match. First he discusses how overlap depends on hybridization; then how bond strength depends on the number of shared electrons. In this way quantum mechanics shows that Co ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride begins by using previous examples of "pathological" bonding and the BH3 molecule to illustrate how a chemist's use of localized bonds, vacant atomic orbitals, and unshared pairs to understand molecules compares with views based on the molecule's own total electron density or on com ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
This lecture continues the discussion of the HOMO/LUMO view of chemical reactivity by focusing on ways of recognizing whether a particular HOMO should be unusually high in energy (basic), or a particular LUMO should be unusually low (acidic). The approach is illustrated with BH3, which is both acidi ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Continuing the examination of molecular orbital theory as a predictor of chemical reactivity, this lecture focuses on the close analogy among seemingly disparate organic chemistry reactions: acid-base, SN2 substitution, and E2 elimination. All these reactions involve breaking existing bonds where LU ...
Leto:
2008
Vir:
videolectures.net