Local Electronic Correlation in Multicomponent Møller-Plesset Perturbation Theory.

Area of Science:

• Quantum chemistry
• Computational physics
• Theoretical chemistry

Background:

• Multicomponent methods are crucial for simulating quantum nuclear effects.
• Current methods often rely on computationally expensive canonical formulations.
• Local correlation, particularly with Pair Natural Orbitals (PNOs), offers a more efficient alternative.

Purpose of the Study:

• To apply local correlation techniques within multicomponent quantum simulations.
• To improve the computational efficiency of describing nuclear quantum effects.
• To benchmark the accuracy and scaling of the new methodology.

Main Methods:

• Implementation of density-fitted NEO-MP2 and NEO-PNO-LMP2.
• Extension of electronic correlation treatment to PNO local coupled cluster.
• Application of local correlation in multicomponent quantum mechanical calculations.

Main Results:

• Demonstrated asymptotically linear scaling of computational costs.
• Achieved high accuracy comparable to traditional methods.
• Showcased efficient calculation of anharmonic corrections for X-H stretches.

Conclusions:

• Local correlation methods significantly enhance the efficiency of multicomponent simulations.
• The developed approach provides accurate and cost-effective modeling of nuclear quantum effects.
• This work paves the way for routine application in complex chemical systems.