文摘
The orbital-based natural language describing the complexity of chemistry (Stowasser, R.; Hoffmann, R. J. Am. Chem. Soc. 1999, 121, 3414) was extended by us recently to the definition of spin鈥搊rbit natural spinors (Zeng, T. et al. J. Chem. Phys. 2011, 134, 214107). This novel method gives chemical insights into the role of spin鈥搊rbit coupling in covalent bonding and in the Jahn鈥揟eller effect. The natural spinors are used to explain antibonding spin鈥搊rbit effects on TlH and Tl2: it is found that the spin鈥搊rbit induced charge transfer from the bonding to the nonbonding or antibonding orbitals has a large effect on the bond strength. The natural spinors are also used to explain the spin鈥搊rbit quenching of the Jahn鈥揟eller effect in WF5: the spin鈥搊rbit interaction can stabilize the totally symmetric electron distribution so that the high-symmetry molecular structure becomes more stable than its distortions. A general discussion of the role of the spin鈥搊rbit coupling in covalent bonding and Jahn鈥揟eller effect is given in terms of the competition between the rotational nature of the spin鈥搊rbit coupling and the directionality of the two effects. The natural spinors offer the advantage of providing a simple and clear pictorial explanation for the profound relativistic spin-dependent interactions in chemistry often appearing as a black box answer.