Computational Chemistry Introduction to the Theory and Applications

The second edition of this popular textbook has been revised to improve explanations and to add topics which were not featured in the first edition. It also contains extended, updated examples and references. The questions (the hallmark of a genuine textb

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Chapter 1, Harder Questions, Answers Q1 Was there computational chemistry before electronic computers were available? Computational chemistry as the term is now understood arose at about the same time as electronic computers became available to chemists: In 1951 an international conference was held at Shelter Island near Long Island in New York, N.Y. Most of the leading figures in quantum chemistry were present. Two persons there symbolized the phasing out of desktop mechanical calculators (Prof. Kotani from Japan) and the phasing in of electronic digital computers (Prof. Roothaan of the United Sates). That was the first major conference with a focus on the emerging computer in theoretical chemistry [1].

With heroic effort, one of the very first molecular mechanics calculations, on a reasonably big molecule (a dibromodicarboxybiphenyl), was done by the Westheimer group, ca. 1946, presumably with at most a mechanical calculator [2]. Molecular mechanics is genuine computational chemistry, but is far less numerically intensive than quantum mechanical calculations. Nothing remotely like the quantity and level of complexity of the calculations we see today would be possible without electronic computers. One can make a case that computational chemistry without the electronic computer was essentially stillborn, ca. 1950. To be fair, H€ uckel molecular orbital calculations, which can be executed with pencil and paper, might legitimately be held to fall within the purview of computational chemistry, and these were first done in the 1930s [3] (attaining great popularity in the 1950s and 1960s [4]). Computational chemistry thus blends into traditional theoretical chemistry, a good part of which – much of chemical thermodynamics – was almost singlehandedly created in the late 1800s, by Josiah Willard Gibbs [5]. Histories of the development of computational chemistry in various countries can be found in the continuing series Reviews in Computational Chemistry [6]. E.G. Lewars, Computational Chemistry, DOI 10.1007/978-90-481-3862-3, # Springer ScienceþBusiness Media B.V. 2011

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References 1. Lykos P (1997) Chapter 2 “The evolution of computers in chemistry. In: Zielinski TJ, Swift ML (eds) Using computers in chemistry and chemical education. American Chemical Society, Washington DC 2. (a) Westheimer FH, Mayer JE (1946) J Chem Phys 14:733. (b) Hill TL (1946) J Chem Phys 14:465. (c) Westheimer FH (1947) J Chem Phys 15:252. (d) Dostrovsky I, Hughes ED, Ingold CK (1946) J Chem Soc 173 3. H€uckel E (1931) Z Physik 70:204, and subsequent papers (see H€ uckel E (1975) Ein Gelehrtenleben. Ernst und Satire. Verlag Chemie, Weinheim, pp 178–179) 4. E.g. (a) The pioneering popularization: Roberts JD (1962) Notes on molecular orbital calculations. Benjamin, New York. (b) A detailed treatment: Streitweiser A (1961) Molecular orbital theory for organic chemists. Wiley, New York. (c) Perhaps the definitive presentation of the simple H€ uckel method is Heilbronner E, Bock H (1968) Das HMO Modell und seine Anwendung. Verlag Ch