© ab initio
The term "Ab initio" is Latin for
"from the beginning". This name was given to the calculation of
derived directly from theoretical principles, with no inclusion of experimental
data. Most of the time this is referring to the approximate calculation of
quantum mechanics. Estimates are made usually mathematical approximations, such
as using simple functional form for function or obtain approximate solutions to
a differential equation.
© Semiempirical
Semiempirical calculations are set with the same
general structure as the calculation of HF. Within this framework, certain
pieces of information, such as two electron integrals, which approximated or
completely eliminated. In order to correct the errors introduced by removing
part of the calculation, this method parameters, by curve fitting in some
parameters or numbers, to provide the best possible agreement with the data
eksperimen.Sisi both semiempirical calculations is that they are much faster
than the ab initio.
© Modeling solid state
The electronic structure of an infinite crystal band
is defined by the plot structure, which gives the energy of electron orbitals
for each point in k-space, called the Brillouin zone. Since ab initio and
semiempirical calculations yield orbital energies, they can be applied to band
structure calculations. However, if it takes time to calculate the energy of
the molecule, it is even more time consuming to calculate the energy for a list
of points in the Brillouin zone.
© Mechanics molecule
If the molecule is too large to effectively use
semiempirical treatment, it is still possible to model the behavior of quantum
mechanics to avoid completely. A method called molecular mechanics form simple
algebraic expression for the total energy compounds, without having to
calculate the wave function or total electron density. Energy expression
consists of simple classical equations, such as the harmonic oscillator
equation in order to describe the energy associated with bond stretching,
bending, rotation and intermolecular forces, such as van der Waals interactions
and hydrogen bonding. All constants in this equation must be obtained from
experimental data or ab initio calculations.
© molecular dynamics
Molecular dynamics consists of checking the
time-dependent behavior of molecules, such as vibrational motion or Brownian
motion. This is most often done in a classical mechanical description similar
to the molecular mechanics calculations. Application of molecular dynamics to
solvent / solute system allows the calculation of properties such as diffusion
coefficient or radial distribution functions for use in the treatment of
statistical mechanics. Usually the calculation scheme solvent / solute is that
the number of molecules (possibly 1000) given some initial position and
velocity. calculating new positions small time later based on this movement and
this process itterated for thousands of steps to bring the system to balance
and provide a good statistical picture of the radial distribution function.
© Thermodynamics
Thermodynamics is one of the most well-developed
chemical description of mathematics. Very often any thermodynamic treatment is
left for trivial pen and paper work for many aspects of chemistry so accurately
described by a very simple mathematical expressions.
© Structure-Property Relationship
Structure-property relationships are qualitative or
quantitative empirically defined the relationship between molecular structure
and properties were observed. In some cases this may seem to duplicate the
results of statistical mechanics, however structure-property relationships need
not be based on rigorous theoretical principles. The simplest case of structure-property
relationships of qualitative rules of thumb. For example, experienced polymer
chemist may be able to predict whether the polymer will be soft or brittle
based on geometry and bonding of the monomers.
© Symbolic Calculations
Symbolic computation is done when the system is too
big for a description of the atom-by-atom is still worth at every level
approach. An example might be an idea to explain lipid membrane individuals as
representatives of some of the polygon with some expression for the interaction
energy. This kind of treatment is used for computational biochemistry and even
microbiology.
© Artificial Intelligence
Technique invented by computer scientists interested
in artificial intelligence have been applied mostly drug design in recent
years. This method also goes by the name of De Novo or rational drug design. A
common scenario is that some of the functional sites have been identified and
it is desirable to come up with a molecular structure that will interact with a
site that's blocking the function. Rather than have a chemist try hundreds or
thousands of possibilities with molecular mechanics program, molecular
mechanics built into the artificial intelligence program, which tries large
amount "reasonable" possibility in the automated fasion. The number
of techniques to describe the "smart" part of this operation is so
diverse that it is impossible to make generalizations about how this is
implemented in the program.
© Visualization
Data visualization is the process of displaying
information in a kind of pictorial or graphical representation. A number of
computer programs are now available to apply the coloring scheme of data or
working with three-dimensional representation.
© Mechanics Statistics
Statistical mechanics is a mathematical way to
extrapolate thermodynamic properties of the material as a whole (bulk) rests on
a molecular picture of matter. Many are still at the level of statistical
mechanics paper and pencil method, because experts have not been able to
resolve the quantum mechanics Schroedinger equation is an inexact until now so
expert statistical mechanics did not have a starting point to develop a method
of settlement. Calculation of statistical mechanics is often done at the end of
ab initio calculations of the properties of the gas phase. For condensed phase
properties, often molecular dynamics calculations needed in order to perform
computational experiments. One method that is widely used statistical mechanics
in computational chemistry is Monte Carlo. With the Monte Carlo method, we can
get an overview of the structure and the energy balance, but it can not provide
a picture or sifatyang dynamics depend on time.
© Orbital Gaussian or Gaussian-type orbitals (GTOs)
is a mathematical function that states atomdalam
orbital molecular orbital calculation. Gaussian orbital been given the
similarity of its shape function with fungsiorbital atom. For comparison
function atomic orbitals.
© Statistics
is
the study of how to plan, collect, analyze, interpret, and present data. In
short, statistics is the science with respect to data. The term 'statistics'
(English: statistics) differs from the 'stats' (statistic). Statistics is the
science with respect to data, while statistical data, information, or the
result of applying statistical algorithms on the data.
© Parallel Computing
is one technique to compute simultaneously by
utilizing multiple independent computers simultaneously. It is generally
required when the required capacity is very large, either because they have to
process large amounts of data (in the financial industry, bioinformatics, etc.)
or because of the demands of the computing process that much. Both cases are
common in the numerical calculations to solve mathematical equations in physics
(computational physics), chemistry (computational chemistry) etc.
© GAMESS or General Atomic And Molecular Electronic
Structure System
Is software for chemical calculations kuatum
developed under the UK.
© Molecular docking
is a technique used to study the interaction of a
complex molecule. Molecular docking to predict the orientation of a molecule to
another molecule when it binds to form a stable complex. (Funkhouser, 2007).
© OV (Orbital Viewer)
is a free software to describe atomic and molecular
orbitals, create animations and to see cross section (structures inside)
orbital. 3D images can also be made (which can be viewed with 3D glasses as He
used to see 3D soap opera.
© BS (Balls & Sticks)
is a free software to describe the chemical
structure, especially crystal, in 3D and can produce a bitmap image that can be
copied to clipboard and pasted (paste) in a word processing document (Word for
example).
© Molecular Operating Environment (MOE)
developed Chemical Computing Group
(www.chemcomp.com). MOE addition to offering complete facilities are also
user-friendly so suitable for use in learning. Only computational chemistry
applications are user-friendly so that is usually expensive cost efficiency
reasons no longer relevant.
© theoretical chemistry
is defined as a mathematical description of
chemistry. The term computational chemistry is always used if a mathematical
method is intended to be run automatically by the computer.
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