
	Where results make sense

Topic: Gaussian orbital

Related Topics

Standard C programming language

Red imported fire ant

Tracford

Phoenix Consortium

Eli Whitney

Olive family

Maurice Leblanc

Dagami, Leyte

	NationMaster - Encyclopedia: Gaussian orbital
		In molecular physics, Gaussian orbitals are a mathematical technique used for the computation of electron orbitals in molecules.
		Gaussians for short, are functions used as atomic orbitals in the linear combination of atomic orbitals molecular orbital method.
		By default, Gaussian prints molecular orbitals and performs population analyses regarding the MO coefficients from a semi-empirical calculation as coefficients of orthogonalized atomic orbitals (OAO's).
	www.nationmaster.com /encyclopedia/Gaussian-orbital (453 words)

	Gaussian 03 Release Notes
		The reference for the APT charges included in the output for some Gaussian calculations is: J. Cioslowski, JACS 111 (1989) 8333.
		We have added OmPW ("old mPW") as a functional which includes the error and is thus consistent with Gaussian 98 and the results (but not the equations) in the original paper.
		While these conditions are almost always the result of a poorly chosen model system, Gaussian 03 now recognizes this condition and turns off symmetry, so that the calculation proceeds as requested.
	www.gaussian.com /g_tech/g03_rel.htm (3466 words)

	G
		Phys., 27, 789 (1974) (2) gauge-including atomic orbital (3) gauge invariant atomic orbital
		gaussian orthogonal ensemble (of random matrices in quantum chaoticity study in atomic and nuclear energy levels)
		gaussian unitary ensemble (of random matrixes in quantum-transport studies)
	www.iupac.org /reports/1996/6802brown/g.html (388 words)

	LRZ: The Gaussian Quantum Chemistry Package
		Gaussian is a connected system of programs for performing semi-empirical and ab initio molecular orbital (MO) quantum chemical calculations.
		Gaussian may only be used for academic and teaching purposes in institutes associated with Bayerische Akademie der Wissenschaften, the Munich Universities and the Munich Fachhochschulen.
		There is a list of Gaussian reference manuals available on the web as well as an order form which needs to be printed out, filled in and faxed to Gaussian Inc.
	www.lrz-muenchen.de /services/software/chemie/gaussian (1239 words)

	No Title
		Early, the Slater Type Orbitals (STO's) were used as basis functions due to their similarity to atomic orbitals of the hydrogen atom.
		DZ sets have two basis functions per orbital, etc. Since valence orbitals of atoms are more affected by forming a bond than the inner (core) orbitals, more basis functions are assigned frequently to describe valence orbitals.
		Frequently, the core orbitals are long contractions consisting of many primitive gaussians to represent well the "cusp" of s type function at the position of the nucleus.
	www.ccl.net /cca/documents/basis-sets/basis.html (5465 words)

	Brian Hoffman's Publications (Site not responding. Last check: )
		In the expression for the GTO, the orbital exponent
		defines the spatial extent of the orbital; whereas, the sum of the exponents a, b, and c represents the angular momentum.
		Gaussian functions do not have a cusp at the nucleus and do not fall-off correctly far from the nucleus, but they have the advantage of being much easier to use.
	zopyros.ccqc.uga.edu /~hoffbc/Source/scf/node11.html (522 words)

	Bambooweb: Gaussian orbital
		Gaussians for short, are functions used as atomic orbitals in the linear combination of atomic orbitals molecular orbital method.
		In 'spherical Gaussian type orbitals', the angular part is replaced by true spherical harmonics $Y_{lm}(\theta,\phi), where l is the angular momenta (see also electron configuration).$
		The principal reason for the use of Gaussian basis functions in molecular quantum chemical calculations is the 'Gaussian Product Theorem', which guarantees that the product of two GTOs centered on two different atoms is a finite sum of Gaussians centered on a point along the axis connecting them.
	www.bambooweb.com /articles/g/a/Gaussian_orbital.html (440 words)

	[No title]
		The molecular orbitals (typically spin orbitals) are constructed from a basis set of one-electron atomic orbitals,.
		Gaussian 98 is a connected system of programs for performing a variety of semi-empirical and ab-initio molecular orbital (MO) calculations.
		Gaussian is used to perform fundamental research in chemical, pharmaceutical and material sciences, in academic and commercial settings.
	www.lycos.com /info/molecular-orbital--molecular-orbitals.html (382 words)

	[No title]
		One selects a set of active orbitals and active electrons, then forms all of the configurations possible by placing the active electrons in the active orbitals, consistent with the proper spin and space symmetry requirements.
		Orbitals that contain e- are occupied, those that are vacant are called "virtual." The orbital for each electron is determined in the average field of the other electrons, and iterated until self-consistency is achieved.
		In Gaussian nomenclature, 3-21G is a split valence basis, and 6-311G is a triple-split-valence basis.
	www.chamotlabs.com /Freebies/ModelRef.txt (4428 words)

	Basis Sets
		This means we are summing 3 gaussians for the inner shell orbital, two gaussians for the first STO of the valence orbital and 1 gaussian for the second STO.
		atomic orbitals as existing only as 's', 'p', 'd', 'f' etc. Although those basis sets are good approximations, a better approximation is to acknowledge and account for the fact that sometimes orbitals share qualities of 's' and 'p' orbitals or 'p' and 'd', etc. and not necessarily have characteristics of only one or the other.
		In this case, 's' orbitals begin to have a little of the 'p' flavor and 'p' orbitals begin to have a little of the 'd' flavor.
	www.shodor.org /chemviz/basis/teachers/background.html (1466 words)

	The Absolute Beginners Guide to Gaussian
		The Gaussian programs are given version numbers according to which year they were released (i.e.
		Gaussian is a program for doing ab initio and semiempirical calculations on atoms and molecules.
		Gaussian itself currently has no provisions for graphical or interactive inputs or outputs.
	www.ccl.net /cca/documents/dyoung/topics-orig/gaussian.html (1728 words)

	CCCBDB computational thermochemistry glossary (Site not responding. Last check: )
		The set of orbitals is called the "active space," and the specified electrons are called "active." In many cases, it requires experience and skill to select the active space correctly.
		Orbitals are probably the most useful concept from quantum chemistry: one can think of an atom or molecule as having a set of orbitals that are filled with electrons (occupied) or vacant (unoccupied or "virtual").
		The orbitals (i.e., the coefficients of the atomic basis functions in each molecular orbital) are adjusted until they are optimal in the mean electric field that they imply.
	srdata.nist.gov /cccbdb/glossary.asp (4608 words)

	Gaussian
		Gaussian is a connected system of programs for performing semiempirical and ab initio molecular orbital calculations.
		Gaussian uses several scratch files in the course of its computation.
		Also, Gaussian will use up to 4 processors during the run; this should be specified on the command line via the -n flag so that the batch system allocates the correct number of processors.
	helix.nih.gov /apps/structbio/gaussian (986 words)

	Gaussian-Type Functions
		The advantage of the Gaussian function is that less computer time is required to evaluate the integrals in the
		This problem is solved by replacing each orbital in the minimal basis set with two basis functions that differ in size.
		In addition, six d-type Gaussian functions for each nonhydrogen atom in the second or third period are included in the basis set.
	www.chm.davidson.edu /ronutt/che401/Gaussian/Gaussian.htm (599 words)

	Gaussian on Biowulf
		Gaussian can predict energies, molecular structures, vibrational frequencies-along with the numerous molecular properties that are dervied from these three basic computation types-for systems in the gas phase and in solution, and it can model them in both their ground state and excited states.
		When the L0 command '%chk=' is given in a Gaussian command script, and the stated checkpoint file already exists, Gaussian attempts to import the checkpoint file and begin running with data from the file.
		Gaussian errors are not always straightforward to interpret.
	biowulf.nih.gov /apps/gaussian (1907 words)

	Internal Basis Sets in Gaussian94
		Orbitals that are present when polarization functions are added will be given in bold, while those that are included when diffuse functions are added will be given in italics.
		The 2p and 3p orbitals are composed of 6 and 3 Gaussians, respectively, while the 4p orbitals are split into two orbitals with one Gaussian each.
		The occupied 3d-orbitals are composed of 5 Gaussians.
	fconyx.ncifcrf.gov /~lukeb/GauBas.html (3821 words)

	Research Computing Technologies
		Gaussian is a connected system of programs for performing semi-empirical and ab initio molecular orbital (MO) calculations.
		Gaussian 98 can be executed in serial mode on a single node or in parallel mode on multiple cluster nodes for improved throughput.
		To print the output from a Gaussian 98 job, use the sftp or scp command to transfer the output file to a machine which does have printing capabilities, such as your personal workstation, and print the output from that machine.
	www.ats.ucla.edu /rct/software/chemistry/gaussian98.htm (1041 words)

	[No title]
		Gaussian is a federally registered trademark of Gaussian, Inc. This software is provided under written license and may be used, copied, transmitted, or stored only in accord with that written license.
		Initial guess orbital symmetries: Occupied (A1) (A1) (?A) (?A) (A1) Virtual (A1) (E) (E) (A1) (E) (E) (A1) (A1) (?A) (?A) (?A) (?A) (A1) (?A) (E) (E) Requested convergence on RMS density matrix=1.00D-08 within 64 cycles.
		The smallest eigenvalue of the overlap matrix is 1.856D-02 Initial guess read from the read-write file: Initial guess orbital symmetries: Occupied (A1) (A1) (?A) (?A) (A1) Virtual (A1) (E) (E) (E) (E) (A1) (A1) (E) (E) (A1) (?A) (?A) (A1) (?A) (?A) (A1) Requested convergence on RMS density matrix=1.00D-08 within 64 cycles.
	web.missouri.edu /~glaserr/433f02/hydroniumG1.log (3610 words)

	Cube Keyword
		The Cube properties keyword can be used to evaluate molecular orbitals, the electrostatic potential, the electron density, density gradient, the norm of the density gradient, and Laplacian of the density over a 3 dimensional grid (cube) of points.
		Gaussian 98 provides reasonable defaults for grids, so Cube no longer requires that the cube be specified by the user.
		If the Orbitals option is selected, the cube filename (or cube filename and cube specification input) is immediately followed by a list of the orbitals to evaluate, in free-format, terminated by a blank line.
	www.nersc.gov /nusers/resources/software/apps/chemistry/gaussian/g98/00000430.htm (1035 words)

	Jmol Wiki - Gaussian
		Most Gaussian releases are supported (94, 98, 03), and the IO reads the all structures, sequentially, and some additional information.
		Because Gaussian outputs the orientation(s) of the last scan point after it is done, one ends up with one branch more than expected.
		Orbital information written in a cube file will be read and displayed by Jmol.
	wiki.jmol.org /index.php?title=Gaussian&printable=yes (343 words)

	Laboratory for Molecular Simulation
		Gaussian 98 is a suite of programs to perform semi-empirical and ab initio Molecular Orbital Calculations.
		Gaussian 98 has been replaced by Gaussian 03 and is only available on chmsgi, k2, and agave.
		Gaussian 98 version A.11 is available on k2.
	www.chem.tamu.edu /LMS/gaussian_98.html (427 words)

	Basis Sets
		The 6 represents the 6 gaussian primitives used to calculate the s-shell, the 3 represents the number of GTOs for one of the sp-shells and each 1 represents the number of GTOs for the other two sp-shells.
		With carbon, you see the addition value, so the first is the orbital exponent, the second is the s-part of the sp-hybrid, and the third part is the p-part of the sp-hybrid.
		With C, the s-orbital is a core orbital, and is represented by 6 gaussian primitives.
	www.shodor.org /chemviz/basis/students/background.html (1398 words)

	NDSU CHPC/Software/Gaussian Home Page
		Gaussian 03 is a connected system of programs for performing semi empirical, ab initio, and density functional molecular orbital (MO) calculations.
		Gaussian 03 is on the HP Itanium-2, Altix and the Intel P4 Linux Cluster.
		Gaussian 03 input file consists of a series of lines in an ASCII text file.
	www.ndsu.nodak.edu /chpc/gaussian.htm (311 words)

	A historical trip with molecular hydrogen calculations
		The single 1s orbital on each hydrogen, although not scaled for the hydrogen molecule, has its STO exponent selected to fit the hydrogen atom in a molecular environment, in particular when bonded to carbon (the exponent z is close to 1.2).
		The molecular orbital calculation selects the optimum combination of the orbitals and this is equivalent to a single orbital of optimum size.
		This method of scaling orbitals is not efficient and, as mentioned earlier, it is not the method normally used.
	www.chem.swin.edu.au /modules/mod8/hydrogen.html (2849 words)

	physics - Gaussian orbital
		The speedup by 4--5 orders of magnitude compared to Slater orbitals more than outweighs the extra cost entailed by the larger number of basis functions generally required in a Gaussian calculation.
		For reasons of convenience, many Gaussian integral evaluation programs work in a basis of Cartesian Gaussians even when spherical Gaussians are requested: the 'contaminants' are deleted a posteriori.
		A visualization of all common and uncommon atomic orbitals, from 1s to 7g Note that the radial part of the expressions given corresponds to Slater orbitals rather than Gaussians.
	www.physicsdaily.com /physics/Gaussian_orbital (524 words)

	Theoretical Chemistry 1968-76
		A series of papers was published examining and testing methods for approximating so-called "molecular orbitals".
		Ab initio molecular orbital calculations using Gaussian orbital basis sets were carried out for a large variety of structures of the hydrated proton and hydroxyl ion, H
		Calculated solvation enthalpies, based on energy-optimized structures, were calculated to be within a few kilocalories of experimental values (after corrections for zero-point energy differences were made), and the experimentally observed similarities of enthalpies for isoelectronic cations and anions were reproduced.
	www.bnl.gov /chemistry/History/TheoreticalChemistry1968-1976.asp (1174 words)

	Viewing Molecular Orbitals with Chem3D
		Viewing orbitals after a Gaussian calculation is a simple procedure with Chem3D.
		When running the Gaussian calculation there are two ways in which you can get the desired formatted checkpoint file.
		After the Gaussian calculation is complete, open Gaussian.
	educ.gaussian.com /visual/Orbs/html/OrbsChem3D.htm (290 words)

	The Properties of Reactant Molecules
		It is much easier if the R group is already ionic, because then moving the charge from one part of the molecule to another takes little energy and no change in ionicity, and hence eliminates the need for any solvation treatment.
		Because these two orbitals are essentially the same in energy, they have to be considered together; the only position where both of them do have density is in the meta position.
		Molecular orbital methods can help identify the origin of the aromaticity (from the nature of the MOs themselves) and the quantitative value of the aromaticity using an computed index known as NICS.
	www.ch.ic.ac.uk /local/organic/mod/mo_4.html (3343 words)

	Basis Sets
		Typically, the basis functions are centered on the atoms, and so sometimes they are called ``atomic orbitals.'' However, it is important to note that this does not imply that they are actually solutions to the electronic Schrödinger equation for the atom.
		Since the highest angular momentum orbital for carbon is a p orbital, the ``polarization'' of the atom can be described by adding a set of d functions.
		This obscure notation means that the core orbital is described by a contraction of 6 Gaussian orbitals, while the valence is described by two orbitals, one made of a contraction of 3 Gaussians, and one a single Gaussian function.
	vergil.chemistry.gatech.edu /courses/chem4681/background/node5.html (654 words)

Try your search on: Qwika (all wikis)