A general time-domain formulation of equation-of-motion coupled-cluster theory for linear spectroscopy

Area of Science:

• Quantum chemistry
• Computational spectroscopy
• Theoretical chemistry

Background:

• Equation-of-motion coupled-cluster (EOM-CC) theory is a powerful method for calculating electronic excitation energies.
• Existing time-dependent (TD) EOM-CC methods have limitations in their applicability to various spectroscopic techniques.
• Accurate theoretical modeling is crucial for interpreting experimental spectroscopic data.

Purpose of the Study:

• To develop a general time-dependent (TD) formulation of equation-of-motion (EOM) coupled-cluster (CC) theory.
• To create a TD-EOM-CC method applicable to all types of linear electronic spectroscopy.
• To investigate the computational advantages and spectral prediction capabilities of the new method.

Main Methods:

• Development of a novel time-dependent formulation for EOM-CC theory.
• Formal equivalence established between the TD-EOM-CC and frequency-domain EOM-CC methods.
• Application of the TD-EOM-CC framework to calculate linear absorption and electric circular dichroism spectra.

Main Results:

• The developed TD-EOM-CC method demonstrates broad applicability across different linear electronic spectroscopies.
• The new approach exhibits a favorable low memory footprint compared to other TD-EOM-CC methods.
• Accurate theoretical spectra were obtained for small oxirane derivatives, validating the method's performance.

Conclusions:

• The generalized TD-EOM-CC theory provides a versatile and computationally efficient tool for electronic spectroscopy.
• This framework overcomes limitations of previous TD-EOM-CC approaches, enabling wider application.
• The method is well-suited for the accurate prediction and analysis of molecular spectra.