Efficient implementation of time-dependent auxiliary density functional theory.

Area of Science:

• Computational chemistry
• Theoretical physics
• Quantum mechanics

Background:

• Standard time-dependent density functional theory (TDDFT) is computationally intensive for large systems.
• Accurate calculation of electronic excitation energies is crucial for understanding molecular properties and reactions.

Purpose of the Study:

• To rederive and validate the random phase approximation of time-dependent auxiliary density functional theory (TDADFT).
• To assess the computational efficiency and applicability of TDADFT for various molecular systems.
• To demonstrate the utility of TDADFT in Born-Oppenheimer molecular dynamics simulations.

Main Methods:

• Rederivation of TDADFT from auxiliary density perturbation theory.
• Implementation of optimized recurrence relations and asymptotic expansions for efficient computation.
• Benchmarking computational scaling with alkanes, fullerenes, DNA fragments, and zeolites.
• Application to Born-Oppenheimer molecular dynamics simulations of polycyclic aromatic hydrocarbons.

Main Results:

• TDADFT shows an approximate 0.1 eV upshift in excitation energies compared to TDDFT.
• TDADFT exhibits favorable computational scaling between 1.3 and 1.9.
• The method's efficiency is demonstrated across diverse molecular sets.
• Temperature effects on gas-phase absorption spectra of benzene, naphthalene, and anthracene were successfully simulated.

Conclusions:

• TDADFT provides a computationally advantageous alternative to TDDFT for electronic excitation energy calculations.
• The improved scaling makes TDADFT particularly suitable for large-scale molecular dynamics.
• TDADFT accurately captures temperature-dependent spectral properties, enhancing its practical utility.