Publications (7)
Eliminating Delocalization Error through Localized Orbital Scaling Correction with Orbital Relaxation from Linear Response
Yichen Fan, Jincheng Yu, Jiayi Du +1
Despite the great success that Kohn-Sham density functional theory (KS-DFT) has achieved, the delocalization error remains a major challenge for commonly used density functional ap…
Orbital Energies Are Chemical Potentials in Ground-State Density Functional Theory and Excited-State SCF Theory
Weitao Yang, Yichen Fan
We prove the general chemical potential theorem: the noninteracting one-electron orbital energies in DFT ground states and SCF excited states are corresponding chemical potenti…
Velocity Gauge for Oscillator Strength in SCF theory
Yang Shen, Yichen Fan, Weitao Yang
Delta self-consistent-field (SCF) theory is widely used for electronic excitation energy calculations. However, calculating the corresponding oscillator strengths is challengin…
Occupancy Extrapolation: Reaching Many Excited Electronic States from Ground State Calculations
Yichen Fan, Weitao Yang
The SCF DFT approach defines the system energy as a function of orbital occupancy. Inspired by Landau Fermi liquid theory, we develop an occupancy extrapolation (OE) method tha…
Fractional Charges, Linear Conditions and Chemical Potentials for Excited States in Theory
Weitao Yang, Yichen Fan
To describe excited states, the electron density alone being insufficient, we use the noninteracting reference density matrix based on the recently estab…
Excited States from Quasiparticle Hamiltonian Based on Density Functional Theory
Yang Shen, Yichen Fan, Weitao Yang
Recent advances in occupancy extrapolation (OE) show that potential of orbital-occupation based energy functions can describe electronic excitations. Here, the OE method in the par…
olLOSC: Unified and efficient density functional approximation to correct delocalization error in molecules and periodic materials
Yichen Fan, Jacob Z. Williams, Weitao Yang
Density functional theory (DFT) is the most promising method for calculating quantum properties of molecules and materials at moderate and large scales. However, commonly used dens…