A Chemist's Guide to Valence Bond Theory

How valence bond theory can help you understand your (bio)chemical reaction

“…and co-workers. 10,12,13 This value was calculated to be only 222 5 kcal/mol using the VBPCM, which is closer to the 194 kcal/mol value calculated in vacuum than to the estimated value (≥281 kcal/mol) in solution and is a result of the absence of nonequilibrium solvation effects required to calculate the promoted state. 19 Using VB/MM where explicit water molecules are 10 considered, such effects are now accounted for and the value is estimated to be 324 kcal/mol.…”

“…Mixing of all of the structures above (also termed diabatic states) results in adiabatic states, the lowest of which describes the reaction profile (bold curve in Fig. 1C scheme which is often used (see 11,13 and references cited therein):…”

Manipulation of organic polyradicals in a single-molecule transistor

“…(1), we now proceed to give a likely microscopic understanding of this simple three-spin model within a valence bond (VB) picture of the molecule. 32 This gives a description of the low-energy excitations of the molecule. The diagram in Fig.…”

PNOF5 calculations based on the “thermodynamic fragment energy method”: C n H2n+2 (n = 1, 10) and (FH) n (n = 1, 8) as test cases

“…The idea of a function of this type dates back to the early fifties [22,23] and is inspired by the valence bond theory [24,25]; in fact, PNOF5 can also be considered as a type of GVB-PP method with fixed signs for the expansion coefficients of the corresponding determinants. Many scientists have worked actively in the field of strongly orthogonal geminals, and one of them is Professor Péter R. Surján to whom is dedicated this Festschrift.…”

“…In the bottom-up method, the functional was generated by progressive inclusion of known necessary N-representability conditions on the 2-RDM, whereas the top-down method was used through reducing the energy expression generated from an N-particle wavefunction to a functional of the occupation numbers and natural orbitals [5]. In the case of PNOF5, this wavefunction is an antisymmetrized product of strongly orthogonal geminals (APSGs), with the expansion coefficients explicitly expressed by the occupation numbers [20,21].The idea of a function of this type dates back to the early fifties [22,23] and is inspired by the valence bond theory [24,25]; in fact, PNOF5 can also be considered as a type of GVB-PP method with fixed signs for the expansion coefficients of the corresponding determinants. Many scientists have worked actively in the field of strongly orthogonal geminals, and one of them is Professor Péter R. Surján to whom is dedicated this Festschrift.…”