Molecular modelling with spherical Gaussians

Ford, Brian; Hall, G. G.; Packer, J. C.

doi:10.1002/qua.560040508

Cited by 53 publications

(16 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…None of these molecular models exhibited any tendency to numerical instability. Since a cusp function on each heavy nucleus has been used in addition to the bond functions the results compare more directly with those of Ford et al [5] than with Frost. In both calculations it is significant that the total energies are close to 95% of the Hartree-Fock results.…”

Section: Discussionmentioning

confidence: 77%

“…Since its introduction by Frost [1] and its adaptation by others (Preuss [2], Blustin and Linnett [3], Christoffersen [4], Ford et al [5]) the floating spherical gaussian orbital form of wave function has proved to be a vivid and versatile addition to the armory of theoretical methods. In its original form the minimum number of spherical gaussian was used to set up a determinantal wave function and, to compensate for this small basis set, the positions and exponents of all functions were optimized.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Floating s and p-type gaussian orbitals

Brailsford

Hall

Hemming

1975

Chemical Physics Letters

View full text Add to dashboard Cite

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk COLOPHONThe attached paper is another in my series of experiments to see how long it takes me to re-build electronic versions of my published early papers as properly re-typeset 'PDF Normal' rather than just as a bitmap scan.This particular paper appeared in the journal "Chemical Physics Letters" (Elsevier) in 1975. The canonical published version is available online (to subscribers, or for one-off purchase) as a scanned bitmap PDF via: http://www.sciencedirect.com/ The text was acquired by scanning the paper from an offprint and then using Readiris OCR on the resulting TIFF files. The paper was then re-typeset using UNIX troff suite to set up the correct typeface (Times) and to get the line and page breaks as accurate as possible. The tables were re-set using the tbl pre-processor for troff.The time taken to build this paper (over several lunchtimes …) to a reconstituted 'final draft' form was about 4 hours. The advantages of including a small number of p-type gaussian functions in a floating spherical gaussian orbital calculation are pointed out and illustrated by calculations on molecules which previously have proved to be troublesome. These include molecules such as F 2 with multiple lone pairs and C 2 H 2 with multiple bonds. A feature of the results is the excellent correlation between the orbital energies and those of a double zeta calculation reported by Snyder and Basch.

show abstract

Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Floating s and p-type gaussian orbitals

Brailsford

Hall

Hemming

1975

Chemical Physics Letters

View full text Add to dashboard Cite

show abstract

“…But in order to evaluate' second-order properties ', electric and magnetic effects in the main, it is necessary to use the virtual orbitals (Self-Consistent Perturbation Theory [19]) or the virtual states (Rayleigh-Schr6dinger Perturbation Theory [20]) and, of course, there are none of these since all orbitals are doubly occupied. Hall et al [16] recently proposed a method using effectively two FSGOs for the core (actually n/2+ 1 for n electrons in a complete linear plus nonlinear variation). This of course improves the total energy, but has little effect on the valence shell electrons.…”

Section: Discussionmentioning

confidence: 99%

Ab initiocalculations with small ellipsoidal gaussian basis sets. I

Duijnen

Cook

1971

Molecular Physics

View full text Add to dashboard Cite

The use of ellipsoidal gaussian type orbitals in ab initio calculations on molecular systems of small and intermediate size is demonstrated, in both non-linear and SCF MO schemes. The method is an extension of Frost's Floating Gaussian Orbital Method. Results for conformational properties (barriers to internal rotation in ethane and 1,3-butadiene) are better than those obtained with basis sets containing only spherical gaussians. The usefulness of very small basis sets is discussed.

show abstract

“…Hence, with the obvious small modification from the ground state wavefunction formulation, the energy of this quartet state, in a variety of geometrical configurations, was determined using the method of "optimised floating spherical gaussians" [5] (see table 1). In this method a small number of spherical gaussians, generally free to float to any point of the configuration space, and limited only by the constraints imposed by the minimum energy principle, are taken as a basis set {φ} for an HF SCF calculation.…”

Section: Received 10 September 1971mentioning

confidence: 99%