Toward Complementary Characterization of the Chemical Bond

Area of Science:

• Quantum Chemistry
• Chemical Bonding Theory

Background:

• Precise discussion of chemical bonds necessitates two-particle wave functions.
• Understanding intrinsic covalency and atomicity is key to characterizing molecular bonds.

Purpose of the Study:

• To rigorously define and determine the intrinsic covalency and atomicity of the H2 molecule.
• To establish a direct relationship between Mott-Hubbard atomicity and intrinsic covalency/ionicity.

Main Methods:

• Utilizing an analytic form for the two-particle wave function of bonding electrons.
• Singling out atomic contributions (atomicity) and ionic factors.
• Combining single-particle wave function readjustment in entangled states with two-particle state determination in second quantization.

Main Results:

• Defined and determined intrinsic covalency and atomicity for the H2 molecule.
• Demonstrated how atomicity and ionicity factors complement bond attributes.
• Traced the evolution of the molecular state with increasing interatomic distance.
• Established a link between Mott-Hubbard atomicity (Mottness) and intrinsic covalency/ionicity.

Conclusions:

• The study provides a rigorous framework for understanding chemical bond characteristics.
• Introduced atomicity and ionicity as crucial factors complementing existing bond attributes.
• Connected fundamental quantum mechanical descriptions to emergent phenomena like Mottness.