Hoffman, Roald

Hoffman, Roald. The Same and Not the Same. New York Columbia Press, 1995. 

Hoffman, Roald. (1937- ). A Polish-born chemist who won the Nobel Prize for chemistry with Fukui in 1981. His work involved applying the theories of quantum mechanics to predict the course of chemical reactions. 

Hoffman, Roald. 1988. "Nearly Circular Reasoning." American Scientist, 76 182—185. 

One of the simplest approaches to comprehensive molecular orbital calculations is the extended Hiickel method. This method was developed by Roald Hoffman in the 1960s, and it was applied to hydrocarbon molecules. From the discussion presented in Chapters 2 and 3, we know that one of the first things that has to be done is to choose the atomic wave functions that will be used in the calculations. One of the most widely used types of wave functions is that known as the Slater wave functions (see Section 2.4). In the extended Hiickel method, the molecular wave functions are approximated as... 

Dedicated to our great teachers Roald Hoffman, Nicolaos D. Epiotis, Lionel Salem,... 

The various ways to represent MIMs on paper have often been a portrayal of beauty in their own right. In Sect. 3, we tried to engage the beauty of printed molecular representations. There remain many other ways to perceive the beauty of molecular objects, some of them particularly unique to MIMs, but things get messier when we depart from concrete illustrations and images and venture into even more subjective territory. Roald Hoffman, pioneer of molecular aesthetics, has approached beauty in chemistry from the perspective that beauty is built out of individual pleasure around an object or idea [126]. The aesthetic experience of molecular structures is therefore inexorably tied together with our subjective biases. Synthetically derived molecules are retroactively beautified out of a psychological need to associate pleasure with hard work. We find reasons to label a molecule beautiful and experiments elegant, because we invested work, time, and failure to achieve them. Nevertheless, these notions of beauty are common to the experiences of... 

Recent works by Mary Jo Nye, David Knight, Bernadette Bensaude-Vincent and I. Stengers, and Jan Golinski in the history of chemistry Roald Hoffman, Pierre Lazzlo, and Jean-Marie... 

Throughout the studies discussed above, there has been a close interplay between structural measurements and development of theoretical models of molecular electronic structure. Lipscomb s contributions have included topological description of the boron hydrides and fundamental theory. Several coworkers contributed in this area, but most notable is the work with Roald Hoffmann, which changed the way chemists approach the theory of molecules of interesting complexity (see, e.g., the comments in (2(5)). The extended Huckel method was developed in the Lipscomb s group by several people, including especially L. L. Lohr, Jr., and Roald Hoffman (see Roald s recollections in Current Contents Citation Classic, May 8, 1989). Although the method probably contributed more to chemistry than any other method imtil very recently, Lipscomb recalled decades after he introduced it that this method received intense criticism, even denouncement. More exact theory led to the first correct calculation of the rotational barrier in ethane (with R. M. Pitzer in 1963). 

Roald Hoffman (Poland/United States 1937-) and Robert Woodward (United States 1919-1979) and Kenichi Fukui (Japan 1918-1998) described the concept of frontier molecular orbitals and the use of orbital symmetry to explain many reactions that did not appear to proceed by ionic intermediates. The concept of reaction mechanism allows a fundamental understanding of how organic reactions work, and it is a relative latecomer to the study of organic chemistry. It is perhaps the most important aspect, however, because... 

Lastly, chemistry requires commitment. To succeed in this comse, you must commit yourself to learning chemistry. Roald Hoffman, wiimer of the 1981 Nobel Prize for chemistry, said,... 

Nobel Prize in Chemistry 1981 to Kenichi Ftrktri and Roald Hoffman "for their theories. .. concerning the cotrrse of chemical reactions."... 

Excerpt from Roald Hoffman, "Men and Molecules," 1984, Reprinted by permission of... 

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