THEORETICAL CHEMISTRY
Theoretical chemistry is a diverse field of chemistry that uses physics, mathematics and
computers to help us understand
molecular behavior, to simulate molecular phenomena, and to predict the
properties of new molecules. It is common to hear this discipline referred to
as theoretical and computational chemistry.
The advent of computers and the development of software which is
increasingly easy to use has
revolutionized the approach toward understanding chemistry at a fundamental
level and an increase is observed in the number of people interested in
theoretical and particularly in computational
chemistry.
The term computational chemistry is usually used when a mathematical
method is sufficiently well developed that it can be automated for
implementation on a computer. Computational chemistry / molecular modeling is
therefore the science of representing molecular structures numerically and
simulating their behavior with the equations of quantum and classical physics.
Computational chemistry programs allow scientists to generate and present
molecular data including geometries (bond lengths, bond angles), energies
(activation energy, heat of formation), electronic properties (charges,
ionization potential, electron affinity), spectroscopic properties (vibrational
modes, chemical shifts) and bulk properties (volumes, surface areas, diffusion,
viscosity). Over the past ten to twenty years, scientists have used computer
models of new drugs to help define biological activity profiles, geometries and
reactivities.
Theoretical chemistry may be broadly divided into electronic structure and chemical bonding,
reaction dynamics, and statistical mechanics.
Table 1: Main sub-branches of Theoretical Chemistry
CHEMICAL
BONDING
&
ELECTRONIC STRUCTURE
|
STATISTICAL
MECHANICS
|
REACTION
DYNAMICS
|
Lewis Theory of Bonding
|
Quantum Statistics
|
Adiabatic
|
Valence Bond Theory
|
Boltzmann Average
|
Intermolecular
|
Molecular Orbital Theory
|
Partition Functions
|
Intramolecular
|
Covalent Bond Distance
|
Correlation Functions
|
Information Theory
|
Computational chemistry
|
Ensembles
|
Kinematics
|
Ab initio calculations
|
Pair Distribution Functions
|
Molecular Dynamics
|
Semi-empirical calculations
|
||
Modern Valence Bond
|
||
Generalized Valence Bond
|
||
Quantum Chemistry
|
||
Quantum Monte Carlo
|
||
Molecular Modelling
|
||
Molecular Mechanics
|
||
Cheminformatics
|
Chemical Bonding &
Electronic Structure lies at the very core of
Chemistry. It is what enables about one-hundred elements to form millions of
chemical substances.
Reaction dynamics is a field of chemistry, studying why chemical reactions occur in
gases, in liquid, at interfaces and how to predict their behavior and how to
control them.
The main objectives of reaction dynamics are:
· The microscopic foundation of
chemical kinetics
·
State to state chemistry and
chemistry in real time
·
Control of chemical reactions
at the microscopic level
Statistical mechanics sets out to explain the behavior of macroscopic systems by studying
the statistical properties of their microscopic constituents. Applications of
the techniques of statistical mechanics include:
·
Applications to physical
systems such as solids, liquids and gases
·
Applications to colloids,
interfaces, polymers and
No comments:
Post a Comment