Method transition state

Evans M G and Polanyi M 1935 Some applications of the transition state method to the calculation of reaction velocities, especially in solution Trans. Faraday Soc. 31 875-94... 

Ziegler T, Rauk A (1979) CO, CS, N2, PF3 and CNCH3 as donors and acceptors. A theoretical study by the Hartree-Fock-Slater transition state method. Inorg Chem 18 1755 ... 

In Slater s half electron transition state scheme the integral is replaced by a calculation of the orbital energy occupied by half an electron. In the generalised transition state method (GTS) [75] and its related method (UGTS) using unrestricted DFT, the integral is replaced by the expression shown in Equation (14). 

We note at this point that the nonadiabatic-transition state method used here (6,19,77) is not expected to be able to give quantitative agreement with experimental rate constants. There are too many factors that are treated approximately (or not at all) in this theory for such performance to be possible. One of the key difficulties is that calculated rate constants are very sensitive to the accuracy of the potential energy surface at room temperature, an error of lkcalmol-1 on the relative energy of the MECP relative to reactants will equate, roughly speaking, to an error by a factor of five on the calculated rate constant. Even though we... 

Wigner, E. The transition state method, Trans.Faraday Soc, 34 (1938), 29-41... 

Density functional theory was originally formalized for the ground state [1]. It is valid for the lowest energy state in each symmetry class [2,3]. To calculate excitation energies, Slater [4] introduced the transition state method, which proved to be a reasonably good one to calculate excitation energies. 

Approximate density functional theory calculations have been used to investigate the irons influence in [Os(N)(X)4] (X = Cl, Me, SMe) and [Os(N)(Cl)5] ". By using the transition state method the relative effects of steric and electronic stabilization on the trans influence in these complexes have been quantitatively assessed. It is found that the electronic stabilization is greater than the steric stabilization for these complexes. 

Thirdly, the rates of adsorption and desorption could be calculated by means of the transition state method and be equalized. But, bo... 

M.G. Evans and M. Polanyi. Some Applications of the Transition State Method to the Calculation of Reaction Velocities, Especially in Solution. Trans. Faraday Soc., 31 875-894,1935. 

Transition state method discrete variational Xq, calculations. 

Fig. 36. He(I) UPS of Mo,(OCH,CMe3),. The calculated ionization energies for Mo,(OH), using the transition-state method are also shown. (From Ref. 80.)...

XQ transition state method. See Ref. 230. Data from Refs. 79 and 149. 

The interaction of formaldehyde and thioformaldehyde with some group 8 metal-ligand fragments [Ru(CO)4,40 Fe(CO)2(PH3)241] in the rf conformation has been analyzed by the Hartree-Fock-Slater transition-state method... 

T. Ziegler and A. Rauk, Inorg. Chem., 18, 1755 (1979). CO, CS, PF3, and CNCH3 as a Donors and n Acceptors. A Theoretical Study by the Hartree-Fock-Slater Transition-State Method. 

A parameterization method of the Hamiltonian for two electronic states which couple via nuclear distortions (vibronic coupling), based on density functional theory (DFT) and Slaters transition state method, is presented and applied to the pseudo-Jahn-Teller coupling problem in molecules with an s2-lone pair. The diagonal and off-diagonal energies of the 2X2 Hamiltonian matrix have been calculated as a function of the symmetry breaking angular distortion modes and r (Td)] of molecules with the coordination number CN = 3... 

A potential surface is a graphical representation of the energy of the system as a function of its geometry. For a lucid account on potential energy surfaces, transition states, methods for calculating reaction paths, etc., see Chapter 2 in ref. 7. 

Calculations of - reaction rates by the transition-state method and based on calculated - potential-energy surfaces refer to the potential-energy maximum at the saddle point, as this is the only point for which the requisite separability of transition-state coordinates may be assumed. The ratio of the number of assemblies of atoms that pass through to the products to the number of those that reach the saddle point from the reactants can be less than unity, and this fraction is the transmission coefficient , k. (There are also reactions, such as the gas-phase colligation of simple radicals, that do not require activation and which therefore do not involve a transition state.) See also - Gibbs energy of activation, - potential energy profile, - Poldnyi. 

A similar slow evolution from energy to entropy with a final synthesis of both concepts can also be observed in the historical development of chemical kinetics. The energy factor was first pointed out by Arrhenius (1889) when he explained the temperature effect on reaction rates. But in spite of the early work of Kohnstamm and Scheffer (1911) who introduced the idea of activation entropy, the importance of entropy was generally recognized only after Eyring (1935) formulated clearly the thermodynamic treatment of the transition state method. 

---