 Martin Karplus, Michael Levitt and Arieh Warshel received the 2013 Nobel Prize in Chemistry for "the development of multiscale models for complex chemical systems".The term "theoretical chemistry" may be defined as a mathematical description of chemistry, whereas "computational chemistry" is usually used when a mathematical method is sufficiently well developed that it can be automated for implementation on a computer.In theoretical chemistry, chemists, physicists, and mathematicians develop algorithms and computer programs to predict atomic and molecular properties and reaction paths for chemical reactions.