The MRCC program system: Accurate quantum chemistry from water to proteins

Area of Science:

• Quantum Chemistry
• Computational Physics
• Electronic Structure Theory

Background:

• Accurate electronic structure calculations are crucial for understanding molecular properties and chemical reactions.
• Existing quantum chemistry packages may lack efficient implementations of advanced correlation methods or scalability for large systems.

Purpose of the Study:

• To present MRCC, a comprehensive package for ab initio and density functional quantum chemistry.
• To provide efficient implementations of a wide range of correlation methods, including coupled-cluster and density functional theory.
• To enable accurate electronic structure calculations for both small and extended systems.

Main Methods:

• Implementation of various correlation methods: second-order Møller-Plesset (MP2), random-phase approximation (RPA), second-order algebraic-diagrammatic construction [ADC(2)], coupled-cluster (CC), and configuration interaction (CI).
• State-of-the-art coupled-cluster singles and doubles with perturbative triples [CCSD(T)] code.
• Development of arbitrary-order iterative and perturbative CC methods using automated programming.
• Inclusion of multi-reference CC and CI approaches.
• Efficient implementations of density functional theory (DFT) and combined DFT-wave function methods.
• Highly competitive linear-scaling local correlation schemes for extended systems.
• Multi-level approximations and DFT-embedding techniques for accelerating local correlation calculations.
• Interface for quantum mechanics/molecular mechanics (QM/MM) calculations.
• Shared-memory and multi-node parallelization support.

Main Results:

• MRCC provides efficient implementations of low- and high-level correlation methods.
• The package includes advanced features like arbitrary-order CC methods and linear-scaling local correlation schemes.
• MRCC enables accurate calculations for extended systems and supports parallel processing.
• The software is available free of charge for academic purposes.

Conclusions:

• MRCC is a versatile and efficient quantum chemistry package for accurate electronic structure calculations.
• Its advanced methods and scalability make it suitable for a wide range of applications, from small molecules to extended systems.
• The availability of MRCC for academic use promotes research in computational chemistry and physics.