What are some examples of theoretical chemistry?
1 Answer
Theoretical chemistry tends to involve events that can't be easily observed in real life, such as radical reactions, short-lived reaction intermediates, gas-phase reaction dynamics, etc. It can also involve more realistic events that are calculated to save money for the experimentalists.
This can get pretty out-there...
Here are some example published papers where I've distilled the information down into basic...ish summaries.
Theoretical Advanced Inorganic Chemistry
- Can Multiconfigurational Self-Consistent Field Theory and Density Functional Theory Correctly Predict the Ground State of Metal–Metal-Bonded Complexes? by Laura Gagliardi et al.; University of Minnesota
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This paper uses ab initio computational approximations (basically, generating approximate models of the orbital configurations using first principles) to investigate the electronic structure of transition metal complexes in which a metal-metal bond exists.
These might include wave-function-based (
#psi# ) methods like multiconfigurational second-order perturbation theory restricted active space (RASPT2) and density-based (#rho# ) methods such as density functional theory (DFT). The former is indicated as#psi# and the latter is indicated as#rho# in the diagram.These investigated compounds include for instance, those that have
#"Fe"-"Fe"# bonds,#"Fe"-"Mn"# bonds, etc., wherein the#d# orbitals are used to bond directly.
Theoretical f-block Chemistry
- A combined photoelectron spectroscopy and relativistic ab initio studies of the electronic structures of
#"UFO"# and#"UFO"^(-)# by Kirk Peterson et al.; Washington State University
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This paper uses high-level ab initio computational chemistry methods in conjunction with experimental photoelectron spectroscopic studies to investigate the electron correlation within two triatomic uranium-based compounds.
(Plus, it's a great excuse to publish a paper with the word "UFO" in it!).
This dynamical and nondynamical correlation, due to the closeness of adjacent energy levels, includes either short-range electron repulsions, or multiple degenerate electron configurations in the
#5f# and (maybe#6d# ) orbitals.(These near-degeneracies basically make it take a lot longer to model these systems accurately.)
Theoretical Radical Chemistry
- Design of Leaving Groups in Radical
#"C"-"C"# Fragmentations: Through-Bond#2c-3e# Interactions in Self-Terminating Radical Cascades by Igor Alabugin et al.; Florida State University
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Basically, computational modeling was used to predict which leaving groups are best for particular aromatic radical reactions involving
#"Sn"# , such that the transition state is stabilized and the reaction is capably terminated via a#beta# -scission (elimination of a radical fragment to form a double bond).Based on my experience having met Dr. Alabugin in person, I believe this was in conjunction with actual experiment, so that chemical resources are conserved. :)
(That's a common theme of theoretical chemistry: to save money for the experimentalists.)