The following sections discuss how the limitations of Lewis' approach can be overcome, first by extending the theory to account for molecular shapes and then by developing more thorough quantum mechanical theories of the chemical bond.
The more sophisticated quantum mechanical approaches to bond formation are then described, followed by a survey of a number of special cases that raise interesting problems or lead to important insights.
This is somewhat akin to the typical molecular file formats (XYZ, CML, SDF, etc) versus a more structured quantum mechanical log file a snapshot of definite structure versus data discovery and recording.
The monomers with the highest binding scores were then considered for additional calculations using a more accurate quantum mechanical (QM) calculation exploiting the density functional theory (DFT) at B3LYP/6-31G d B3LYP/6-31G d
"If you do this with two atoms, then they behave more like a quantum mechanical object," Dr. Heinrich said.
It is simple and involves only classical physics, making it more accessible than quantum mechanical models.
Don Page, of the University of Alberta, is one of a small band of researchers who are still trying to understand the more philosophical implications of quantum mechanical mathematics.
As a research discipline, chemistry has itself evolved over the last few decades to focus its metaphorical microscope on both far larger and more complex molecular systems than previously attempted, as well as uncovering a far more subtle understanding of the quantum mechanical underpinnings of even the smallest of molecules.
More sophisticated calculations based on quantum mechanical (ah initio) molecular dynamics are needed to explore this problem.[16] At present, however, such calculations are limited to very small systems for very short run times and cannot address the problem of NaCl ion association as done here.
When the mutation affects the active site, more sophisticated and time-consuming Quantum Mechanical computational techniques should be used.
