An atomic orbital based real-time time-dependent density functional theory for computing electronic circular...

Area of Science:

• Computational Chemistry
• Spectroscopy

Background:

• Interpreting electronic circular dichroism (ECD) spectra is challenging due to varying rotatory strength signs and overlapping states.
• Traditional methods like linear-response time-dependent density functional theory (TDDFT) require computing many excited states, which is computationally expensive.

Purpose of the Study:

• To develop and implement an efficient real-time, atomic-orbital based TDDFT method for simultaneous computation of entire ECD spectra.
• To address the limitations of existing methods for large systems with dense electronic states.

Main Methods:

• Implementation of a real-time, atomic-orbital based TDDFT approach.
• Computation of the entire ECD spectrum in a single calculation.

Main Results:

• The new method efficiently computes entire ECD spectra, particularly advantageous for large systems with high density of states.
• The approach is variational, nuclear orientation-independent, and avoids pseudopotential approximations.

Conclusions:

• This real-time TDDFT method offers a more efficient and versatile approach for computing chiroptical properties, including in the X-ray regime.
• It overcomes the computational cost and spectral overlap issues associated with traditional ECD spectral calculations.