Journal of Chemical Physics, Vol.100, No.1, 434-443, 1994
Density-Functional Transition-States of Organic and Organometallic Reactions
Baker’s transition state (TS) locating algorithm was incorporated into the density functional (DF) program deMon. Using this TS locating procedure TSs for several model organic and organometallic reactions were located using both the local density approximation (LDA) and nonlocal (NL) gradient corrected methods. The predicted geometries and relative energetics for the reactions were examined and compared to those of Hartree-Fock HF, post HF, and semiempirical calculations. These calculations indicate that the LDA level of DF theory is not reliable in estimating some reaction barriers and TS structures. However, the NL level of DF theory gave results of the same quality as post HF calculations. Our results clearly demonstrate that DF methods can be used to obtain information as accurate as that obtained using similar quality HF based methods for organic and organometallic systems.
Keywords:DIELS-ALDER REACTION;1;5-SIGMATROPIC HYDROGEN SHIFT;POTENTIAL-ENERGY SURFACES;PHOTO-DISSOCIATION;FORMALDEHYDE;ABINITIO;MECHANISM;BUTADIENE;CIS-1;3-PENTADIENE;APPROXIMATION