Št. zadetkov: 77
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride begins by following Newton's admonition to search for the force law that describes chemical bonding. Neither direct (Hooke's Law) nor inverse (Coulomb, Gravity) dependence on distance will do - a composite like the Morse potential is needed. G. N. Lewis devised a "cubic-octet" theo ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride introduces the theory behind light diffraction by charged particles and its application to the study of the electron distribution in molecules by x-ray diffraction. The roles of molecular pattern and crystal lattice repetition are illustrated by shining laser light through diffract ...
Leto:
2008
Vir:
videolectures.net
Video in druga učna gradiva
Oznake:
chemistry;organic chemistry
Professor McBride uses a hexagonal "benzene" pattern and Franklin's X-ray pattern of DNA, to continue his discussion of X-ray crystallography by explaining how a diffraction pattern in "reciprocal space" relates to the distribution of electrons in molecules and to the repetition of molecules in a cr ...
Leto:
2008
Vir:
videolectures.net
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
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
This lecture brings experiment to bear on the previous theoretical discussion of bonding by focusing on hybridization of the central atom in three XH3 molecules. Because independent electron pairs must not overlap, hybridization can be related to molecular structure by a simple equation. The "Umbrel ...
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