On Electronegativity, Hardness, and Reactivity Descriptors: A New Property-Oriented Basis Set.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Electronegativity is a fundamental chemical concept describing an atom's ability to attract electrons.
• Accurate calculation of electronegativity and related properties is crucial for predicting chemical reactivity.
• Existing basis sets, like 6-311G(d), can yield high error margins in these calculations.

Purpose of the Study:

• To analyze various methods for calculating electronegativity.
• To propose a corrected basis set for improved accuracy and efficiency.
• To evaluate the performance of the proposed basis set for calculating chemical reactivity indices and molecular orbital densities.

Main Methods:

• Review of electronegativity calculation methods and basis set evolution.
• Development and application of a corrected 6-311G(d) basis set.
• Comparison with established basis sets (e.g., Aug-cc-pVQZ, Aug-cc-pV5Z).
• Calculation of electronegativity, hardness, reactivity indices, and frontier molecular orbital densities.

Main Results:

• The standard 6-311G(d) basis set exhibits significant errors in electronegativity calculations.
• The proposed corrected 6-311G(d) basis set achieves accuracy comparable to larger sets like Aug-cc-pVQZ.
• The corrected basis set enables accurate calculations for larger systems due to its low computational cost.
• Calculations of reactivity indices and frontier molecular orbital densities show results consistent with high-quality basis sets.

Conclusions:

• The corrected 6-311G(d) basis set offers a computationally efficient and accurate alternative for calculating molecular properties.
• This improved basis set facilitates reliable studies of chemical reactivity and electronic structure in diverse molecular systems.
• The proposed correction enhances the utility of smaller basis sets in quantum chemical calculations.