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

Usefull programs

[MacMolPlt] will be installed on the cluster. It shall be used to build graphically Gamess input.

xmpg can help to convert Gamess output to XMVB files

xmpo can help to convert .orb files to more handy .bro file (back and forth)

Program of the tutorials (PROPOSAL)

Here are Sason remarks and Philippe remarks I'll include them later on.

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.