VB workshop tutorials program

Instructors

• Benoît Braida
• Zhenhua Chen
• Xun Chen
• David Danovich
• Stéphane Humbel (coordinator)
• Mathieu Linares
• Yirong Mo
• Avital Shurki
• Peifeng Su
• Wei Wu
• Fuming Ying

Program of the tutorials (PROPOSAL)

Tutorial n°1 (Monday p.m) : XMVB program (W. Wu's Group + PC Hiberty )

• Exercices from The Book ... >PCH< (30')
• Work with determinant (det) and with structures with H2

- use Atomic AO's, optimized VBSCF compare to HF CASSCF energies, look at the coefficients.

• Pseudo states (Quasi Classic) : compute |ab|+|ba| then only one determinant. Use it to for in situ bond energy evaluation [ethylene pi bond energy |ab| vs ground state( 4 determinants) ]
• FH (2 structures), F2 : VBSCF, different correlation wave functions (BOVB, VBCI,...), computation of weights and "charge-shift" character, also compare to CASSCF wave functions in the same basis set (probably to provide in order to avoid to spend time there).

Tutorial n°2 (Tuesday p.m): VB applications (A. Shurki + D. Danovitch)

• Exercices from The Book ... >PCH< (30')
• Allyl cation : VB 3 configuration (3rd configuration has a large weight).
• Benzyl radical with most spin alternant determinants (2 determinants) (p228 of The Book) show spin location.
• H2O lone pairs : compute H2O+ states (2 configurations mixing)
• R-X bond dissociation to R. .X and R(+) (-)X for stable ionic dissociation ... via solvent effects? (is that possible with xiamen ?)

(trash: * O2 paradigm : compute singlet - triplet gap : too hard)

Tutorial n°3 (Wednesday p.m): VB vs BDO (Lewis structures) BLW & HuLiS (S. Humbel + M. Linares + Y. Mo )

• Formamid VB & BDO : Evaluate in situ Resonance energy (at a fixed planar geometry) : VB (2 confs, effect of adding the third [(+)N. .C :O(-)] ), B. Distorded Orb. (1 conf (major Lewis Structure) + effect of adding a second conf) + Comparison to thioformamid : same work.
• Butadiene VB & Lewis
• Allyl radical and cation : MO, VB & Lewis (Do these two in VB, BLW and with HuLiS)
• BLW 1 exercice to be proposed by Yirong (Hyperconjugation?)

Possibly use DFT correlated BDO with BLW (find examples where that does improve significantly the analysis)

Tutorial n°4 (Friday p.m): State correlation diagrams ( W. Wu's Group)

• Selected 1,3 dipoles (see with Philippe) : computation of 3-structure D-BOVB wave function, and of the biradical gap, correlation gap vs. barriers
• State correlation Diagrams in 3 centers systems : H3C. - H. - .CH3 (or 4 electrons .... H transfer barrier appearing in F H F(-) when the F ... F distance is increased (which avoids geometry problems).
• Benzen pi system dissymetrization (2 geometries (D6h and D3h); on each geometry 2 spin alternant determinants cf p154 on The Book) - Pbm : check how differentiate sigma vs + (sigma + pi) energies.