Semiclassical transition state theory

{{Short description|Chemical reaction rate theory}}

Semiclassical Transition State Theory (SCTST){{Cite journal|date=2018-02-01|title=Tunnelling and the kinetic isotope effect in CH3+CH4→CH4+CH3: An application of semiclassical transition state theory|journal=Chemical Physics Letters|language=en|volume=693|pages=88–94|doi=10.1016/j.cplett.2018.01.002|issn=0009-2614|last1=Burd|first1=Timothy A.H.|last2=Shan|first2=Xiao|last3=Clary|first3=David C.|url=https://ora.ox.ac.uk/objects/uuid:500ef046-8ad9-43b6-9b49-47cd320d4a71|url-access=subscription}}{{Cite journal|date=1990-08-24|title=Ab initio calculation of anharmonic constants for a transition state, with application to semiclassical transition state tunneling probabilities|journal=Chemical Physics Letters|language=en|volume=172|issue=1|pages=62–68|doi=10.1016/0009-2614(90)87217-F|issn=0009-2614|last1=Miller|first1=William H.|last2=Hernandez|first2=Rigoberto|last3=Handy|first3=Nicholas C.|last4=Jayatilaka|first4=Dylan|last5=Willetts|first5=Andrew}} is an efficient chemical rate theory, which aims to calculate accurate rate constants of chemical reactions, including nuclear quantum effects such as tunnelling, from ab initio quantum chemistry.{{Cite journal |title=An investigation of one- versus two-dimensional semiclassical transition state theory for H atom abstraction and exchange reactions |journal = The Journal of Chemical Physics|volume = 144|issue = 8|last1=Greene |first1=Samuel M. |last2=Shan |first2=Xiao |date=2016-02-28 |pages=084113 |language=en-us |doi=10.1063/1.4942161 |pmid=26931687 |last3=Clary |first3=David C.|url = https://ora.ox.ac.uk/objects/uuid:f40d1c11-38c2-470c-9875-27088663125b}}{{Cite book |chapter=Atmospheric Reaction Rate Constants and Kinetic Isotope Effects Computed Using the HEAT Protocol and Semi-Classical Transition State Theory |last1=Nguyen |first1=Thanh Lam |last2=Barker |first2=John R. |date=2016-08-14 |series=Advances in Atmospheric Chemistry |publisher=World Scientific |pages=403–492 |language=en-us |doi=10.1142/9789813147355_0006 |last3=Stanton |first3=John F.|title = Advances in Atmospheric Chemistry|isbn = 978-981-314-734-8}}{{Cite journal|title=Semiclassical limit of quantum mechanical transition state theory for nonseparable systems|journal=The Journal of Chemical Physics|volume=62|issue=5|pages=1899–1906|doi=10.1063/1.430676|year = 1975|last1 = Miller|first1 = William H.}} The method makes use of the semiclassical WKB wavefunction, Bohr-sommerfeld theory and vibrational perturbation theory to derive an analytical relation for the probability of a particle transmitting through a potential barrier at some energy, E. It was first developed by Bill Miller and coworkers in the 1970's, and has been further developed to allow for application to larger systems{{Cite journal|last1=Barker|first1=John R.|last2=Stanton|first2=John F.|last3=Nguyen|first3=Thanh Lam|date=2010-10-20|title=A practical implementation of semi-classical transition state theory for polyatomics|url=https://utexas.influuent.utsystem.edu/en/publications/a-practical-implementation-of-semi-classical-transition-state-the|journal=Chemical Physics Letters|volume=499|issue=1–3|pages=9–15|doi=10.1016/j.cplett.2010.09.015|issn=0009-2614|url-access=subscription}} and using more accurate potentials.{{Cite journal|title=Improved Multidimensional Semiclassical Tunneling Theory|journal = The Journal of Physical Chemistry A|volume = 117|issue = 49|pages = 13089–13100|last=Wagner|first=Albert F.|date=2013-11-26|language=EN|doi=10.1021/jp409720s|pmid = 24224758}}