GAUSSIAN software package

A series of molecular mechanics and ab initio calculations of an isolated single molecule have been performed with the Gaussian software package (using MM+ and STO-3G, 3-21G, 6-3IG and 6-3IG basis sets, respectively) to explore the expected positions of the peaks corresponding to intramolecular distances and also to determine the optimal procedure to find them. 

The X-Pol method has been implemented in a developmental version of the Gaussian software package Although a single... 

Zhu et al. used Zr and Mg SSNMR experiments in 2008 to examine the local structure within two novel microporous zirconium silicate frameworks, AM-2 and AV-3 [54]. This study used magnetic fields of 9.4 and 21.1 T along with the QCPMG and DFS—QCPMG pulse sequences. In addition, ab initio calculations of Zr EFG tensor parameters were performed using the Gaussian software package [82],... 

CODESSA reads molecular structure files or output files created by other software packages as the starting point for QSAR analysis. It can import computational results from AMPAC, MOPAC, and Gaussian as well as structures in a number of common formats. 

The presence of a single polarization function (either a full set of the six Cartesian Gaussians dxx, d z, dyy, dyz and dzz, or five spherical harmonic ones) on each first row atom in a molecule is denoted by the addition of a. Thus, STO/3G means the STO/3G basis set with a set of six Cartesian Gaussians per heavy atom. A second star as in STO/3G implies the presence of 2p polarization functions on each hydrogen atom. Details of these polarization functions are usually stored internally within the software package. 

Equation (2) was also used to calculate quantum chemical approach. On the basis of previous results [19], calculated electrostatic potentials were computed from ab initio wave functions obtained in the framework of the HF/SCF method using a split-valence basis set (3-21G) and a split-valence basis set plus polarisation functions on atoms other than hydrogen (6-31G ). The GAUSSIAN 90 software package [20] was used. Since ab initio calculations of the molecular wave function for the whole... 

Gaussian elimination is a very efficient method for solving n equations in n unknowns, and this algorithm is readily available in many software packages. For solution of linear equations, this method is preferred computationally over the use of the matrix inverse. For hand calculations, Cramer s rule is also popular. 

There are many computational chemistry software packages available that enable students to make and study the properties of molecules, by quantum mechanics and molecular mechanics methods. These include Gaussian, HyperChem, Spartan, and Biosym. The first four homework problems assume that the student has one of... 

Computational chemistry is essential in a modem physical chemistry course. One approach would be to use laboratory time to have students work through a number of exercises accompanied by elaboration of the concepts in lecture or pre-laboratory discussions. Each of die major computational chemistry software packages come with workbooks or tutorials for learning the software. For example, students can learn by completing exercises in the Spartan tutorials (57). Similar approaches can be taken when using Gaussian (38) and Hyperchem (39) tutorial or exercise collections. 

Band fitting (curve fitting, or band shape analysis) is conveniently performed with commercially available software packages which fit, interactively or automatically, Gaussian or Lorentzian line shapes (or their combinations) to an unknown band profile. The applicability of this technique to lignin chemistry is not known at present. 

The electronic structure calculations were done using the Gaussian 03 quantum mechanical packages. Analyses of the calculations were aided by graphical display of the results. The software packages GausView 03 and Molden were used to examine the structural and vibrational data for the stable clusters and to produce the figures. 

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