Wiberg bond indices

Mulliken bond population Wiberg bond index from NPA... 

At the simplest level are methods for characterizing the bonding pattern of a single state and specified geometry. The BNDIDX keyword leads to printing of a variety of familiEU MO-type bond-order indices as reformulated in terms of NAOs. These include the NAO-Wiberg Bond Index(express-... 

Computations at the B3LYP/cc-pVDZ level have also been used to optimize N-N and C-N bond lengths and to calculate Wiberg bond indexes, lone pair acceptor orbital stabilization interactions, and total energies of twelve azines including 1 <2006ACT2057> see Section 9.01.2.8. 

Uhl and Breher used AIM to understand the bonding in newly synthesized carbaalanes. In particular, the B3LYP/6-31+G(d)) electron density of the model compounds Al8H8(CH)5 (R = H, CCH) shows that each C is connected to one H and four Als via BPs. Each A1 is is connected to one H and three C atoms. The bridging H is connected to four Als, but no BP is discovered between any two Als of the Al8 acube, which is in line with the average Wiberg bond index. 

The Wiberg-bond index (BO) [25] is calculated as sum of the quadratic non-diagonal elements of the density matrix between two atoms. This is done in the NAO-basis. The index has always positive values, therefore one cannot differentiate between bonding and antibonding character of the interaction between the two atoms. 

The first Hilbert space definition of bond order was put forward by Wiberg in 1968 and generalized by Armstrong, Perkins, and Stewart in 1973. Ignoring the nonorthogonalities among basis functions, the Wiberg bond index reads... 

In compound [(CpSiMe3)3U(AlCp )] (Fig. 27), the U-Al bond lengths of two crystallographically inequivalent molecules (3.117(3), 3.124(4) A) are very close to the sum of the covalent radii. A calculated natural charge of 0.540 (0.560) for the AlCp fragment hints toward a small Al-U net charge transfer of 0.091. The Wiberg bond index between U and Al indicates a covalent bond order of ca. 0.5. 

Wiberg bond Indexes (B,), % evolution through the reaction coordinate (%E ), average bond index variation (5Bav)< and synchronicity... 

Wiberg bond index Nalewajski-Mrozek bond index TMBO charge MDQ charge... 

---