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Linear-response theory for Mukherjee's multireference coupled-cluster method: static and dynamic polarizabilities.
1Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany. jagau@uni-mainz.de
The Journal of Chemical Physics
|August 3, 2012
Summary
This study applies response theory to Mukherjee
Area of Science:
- Quantum Chemistry
- Theoretical Chemistry
- Computational Chemistry
Background:
- Response theory is crucial for calculating molecular properties.
- State-specific multireference coupled-cluster (Mk-MRCC) theory offers a framework for complex electronic structures.
- Challenges exist in applying Mk-MRCC to response calculations, particularly concerning dynamic polarizabilities.
Purpose of the Study:
- To derive static and dynamic polarizability expressions using Mk-MRCC theory.
- To investigate the impact of the Mk-MRCC redundancy problem on response functions.
- To develop a working response theory for symmetry-breaking perturbations within Mk-MRCC.
Main Methods:
- Application of response theory formalism to Mk-MRCC.
- Analysis of spurious poles arising from Mk-MRCC redundancy.
- Inclusion of internal excitations in cluster amplitude responses for symmetry-breaking perturbations.
- Calculations using the singles and doubles approximation (Mk-MRCCSD).
Main Results:
- The redundancy in Mk-MRCC theory leads to spurious poles in response functions, hindering accurate dynamic polarizability calculations.
- A functional response theory requires incorporating specific internal excitations when dealing with symmetry-breaking perturbations.
- Illustrative calculations on aryne compounds demonstrate the influence of the multireference ansatz on polarizability.
Conclusions:
- The Mk-MRCC formalism requires modifications to reliably compute dynamic polarizabilities.
- Addressing the redundancy and incorporating specific excitations are key for accurate response theory in Mk-MRCC.
- The study provides insights into the behavior of polarizability in multireference systems.
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