Range-separated hybrid density functionals made simple.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Materials Science

Background:

• Density Functional Theory (DFT) is a powerful computational tool.
• Developing accurate and nonempirical density functionals remains a challenge.
• Range-separated exchange (RSX) hybrids offer improved accuracy but often require empirical parameterization.

Purpose of the Study:

• To present a novel, nonempirical route for deriving RSX hybrid and double hybrid density functionals.
• To generalize the nonempirical determination of the range-separation parameter.
• To improve the modeling of molecular systems and properties sensitive to self-interaction errors.

Main Methods:

• Imposing an additional physical constraint on the exchange-correlation energy.
• Enforcing the reproduction of the hydrogen atom's total energy.
• Generalizing the nonempirical determination of the range-separation parameter for RSX functionals.

Main Results:

• A new, simple, and nonempirical method for deriving RSX hybrid and double hybrid density functionals.
• Successful generalization of the nonempirical range-separation parameter determination.
• Accurate modeling of molecular systems and properties, including ionization potentials.
• Reduction of one- and many-electron self-interaction errors.

Conclusions:

• The proposed nonempirical approach provides a robust framework for developing accurate RSX density functionals.
• This method effectively addresses limitations of existing functionals, particularly for properties prone to self-interaction errors.
• The derived functionals demonstrate high accuracy in modeling various molecular properties.