Locating Transition States By Computational Chemistry
Transition state structures can be determined by searching for first-order saddle points on the potential energy surface (PES). Such a saddle point is a point where there is a minimum in all dimensions but one. Almost all quantum-chemical methods (DFT, MP2 etc.) can be used to find transition states. However, locating them is often difficult and there is no method guaranteed to find the right transition state. There are many different methods of searching for transition states and different quantum chemistry program packages include different ones. Many methods of locating transition states also aim to find the minimum energy pathway (MEP) along the PES. Each method has its advantages and disadvantages depending on the particular reaction under investigation. Summaries of some of the main methods are given below.
Read more about this topic: Transition State
Famous quotes containing the words transition, states and/or chemistry:
“When I was going through my transition of being famous, I tried to ask God why was I here? what was my purpose? Surely, it wasn’t just to win three gold medals. There has to be more to this life than that.”
—Wilma Rudolph (1940–1994)
“I believe the citizens of Marion County and the United States want to have judges who have feelings and who are human beings.”
—Paula Lopossa, U.S. judge. As quoted in the New York Times, p. B9 (May 21, 1993)
“For me chemistry represented an indefinite cloud of future potentialities which enveloped my life to come in black volutes torn by fiery flashes, like those which had hidden Mount Sinai. Like Moses, from that cloud I expected my law, the principle of order in me, around me, and in the world.... I would watch the buds swell in spring, the mica glint in the granite, my own hands, and I would say to myself: “I will understand this, too, I will understand everything.””
—Primo Levi (1919–1987)