Efficient linear-response method circumventing the exchange-correlation kernel: theory for molecular conductance...

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Calculating the frequency domain linear response of molecular systems is crucial for understanding their properties.
• Time-dependent density-functional theory (TD-DFT) is a common method, but often computationally expensive due to the exchange-correlation kernel.
• Previous methods required significant computational resources, limiting their application to smaller systems.

Purpose of the Study:

• To present an iterative approach for calculating the frequency domain linear response of molecular systems.
• To develop a method that avoids the computationally intensive exchange-correlation kernel in TD-DFT.
• To enable the study of larger molecular systems and their responses.

Main Methods:

• An iterative approach was developed to calculate the frequency domain linear response.
• The method circumvents the need to compute the exchange-correlation kernel.
• Virtual orbitals are not required in this computational scheme.

Main Results:

• The presented iterative method successfully calculates the linear response without the exchange-correlation kernel.
• The approach was demonstrated using a jellium model of an elliptic gold cluster.
• The appended theory details the computation of conductance and AC impedance for molecular junctions under bias.

Conclusions:

• This method offers a computationally efficient alternative for studying the response of molecular systems.
• The avoidance of the exchange-correlation kernel and virtual orbitals makes it suitable for large systems.
• The approach has potential applications in understanding molecular junctions and electronic transport.