Recent years have seen an increase in the number of people doing theoretical chemistry. Many of these newcomers are part time theoreticians, who work on other aspects of chemistry as well. This increase has been facilitated by the development of computer software which is increasingly easy to use. It is now easy enough to do computational chemistry that you do not have to know what you are doing to do a computation. As a result, many people don’t understand even the most basic description of how the calculation is done and are therefore successfully doing a lot of work which is, frankly, garbage.The term theoretical chemistry may be defined as the mathematical description of chemistry. The term computational chemistry is usually used when a mathematical method is sufficiently well developed that it can be automated for implementation on a computer. Note that the words exact and perfect do not appear in these definitions. Very few aspects of chemistry can be computed exactly, but almost every aspect of chemistry has been described in a qualitative or approximate quantitative computational scheme. The biggest mistake that a computational chemists can make is to assume that any computed number is exact. However, just as not all spectra are perfectly resolved, often a qualitative or approximate computation can give useful insight into chemistry if you understand what it tells you and what it doesn’t.
Although most chemists avoid the true paper & pencil type of theoretical chemistry, keep in mind that this is what many Nobel prizes have been awarded for.
Source: Young, David [Chem. Aust. 11, 5 (1998)]. Introduction to Computational Chemistry. Retrieved: May 22, 2016 from http://www.ccl.net/cca/documents/dyoung/topics-orig/compchem.html
MSU-IIT Computational Research Group 