Nudged elastic band method in the CRYSTAL code: Theory and Applications.

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• The nudged elastic band (NEB) method is crucial for identifying reaction pathways and transition states.
• Accurate calculations are needed for chemical reactions and phase transitions in condensed matter.

Purpose of the Study:

• To implement and validate various NEB algorithm schemes within the CRYSTAL code.
• To enable accurate transition state characterization using hybrid functionals in condensed matter systems.

Main Methods:

• Implementation of NEB algorithms with force projection, tangent estimation, and optimization strategies.
• Inclusion of climbing image and variable spring constant variants.
• Utilizing localized Gaussian-type functions for efficient hybrid functional calculations in CRYSTAL code.

Main Results:

• Validated NEB implementation through benchmark tests on molecular reactions (proton transfer, keto-enol tautomerization) and a zeolite proton exchange.
• Achieved excellent agreement with experimental and prior theoretical data.
• Demonstrated accurate characterization of transition states at the hybrid functional level.

Conclusions:

• The implemented NEB method in CRYSTAL code accurately characterizes transition states in molecular and condensed phases.
• This advancement facilitates future studies of complex reactive processes in extended periodic systems using hybrid functionals.