Floating s and p-type gaussian orbitals

Abstract

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.

Off‐center Gaussian functions: Applications toward larger basis sets, post‐second‐order correlation treatment, and truncated virtual orbital space in investigations of noncovalent interactions

“…The floating Gaussian orbital approach or the use of midbond functions have the capacity to increase the rate of convergence toward the CBS, and allow for significant savings in terms of the number of basis functions used. For certain molecular systems, such as the benzene dimer, properly placed midbond, or off‐center basis functions can improve results dramatically .…”

“…). This approach is reminiscent of the use of so‐called floating Gaussian orbitals (FGO) but provides straightforward, and generally applicable recipe of how to construct the off‐center basis functions. Our approach necessarily has its drawbacks as well, such as: (i) expansion of the wave function is less satisfactory in highly directional interactions like hydrogen or halogen bonds; (ii) due to the lack of long‐range diffuse basis functions, the expansion of the wave function is less saturated in the interior of the molecule, leading to less accurate description of electric moments at long distances; (iii) loss of cardinality of the basis set, making this approach less suitable for extrapolation, and so forth.…”

The Bruising Business: Pugilism, Commercial Culture and Celebrity, 1700-1750

“…By this point animal baiting was rare at such venues, and by the 1730s and 1740s was 36 Harris, Sport in Newspapers, p.24. 'a cross between a large fairground booth and a theatre' 41 . Byrom records in his journals that entrance cost 2s.…”

“…For some critics this is proof that the prices were designed in order to keep the establishment exclusive 44 Compared to what advertisements were to become the tone is subdued. The names are listed, as is one hometown, but otherwise there is little information to be taken.…”