The latest version of MRCC was released on July 1, 2026.
The important new features and changes are as follows.
1. A linear-scaling integral-direct explicitly correlated second-order MP2 approach.
doi.org/10.1021/acs.jctc.5c02184
2. New CVS-IP-CIS(D), CVS-IP-ADC(2), and double hybrid methods have been implemented for the calculation of core binding energies.
doi.org/10.1021/acs.jctc.6c00015
3. A general-order linear-scaling local coupled-cluster model (both closed- and open-shell).
doi.org/10.1021/acs.jpca.6c00607
4. Frozen natural orbital methods using coupled-cluster natural orbitals.
doi.org/10.1021/acs.jctc.5c01424
5. A self-consistent approach for the basis-set extrapolation of Hartree-Fock energies.
doi.org/10.1007/s11224-025-02542-2
6. Projection-based embedding techniques for open-shell systems.
doi.org/10.1021/acs.jctc.5c00687
7. Implementation of the spin-free exact two-component one-electron (SFX2C-1e) relativistic approach.
doi.org/10.1021/acs.jctc.6c00015
8. A domain-based local approximation has been implemented for IP-ADC(2)- and CVS-IP-ADC(2)-based methods, enabling efficient calculations for large molecular systems.
doi.org/10.1021/acs.jctc.6c00634
9. Open-shell support has been added for CIS, TD-HF, and CIS(D) excited-state calculations.
10. The density-based basis-set correction (DBBSC) approach is now available for open-shell MP2, CCSD(T), and double-hybrid DFT calculations with local natural orbitals.
11. Local embedded subsystem (LESS) approach accelerating Huzinaga embedded HF and hybrid DFT via asymptotically constant AO and DF basis sets.
doi.org/10.1021/acs.jctc.5c01121
12. Memory optimization for CABS and LNO-based DBBSC, especially notable for heavier elements.
13. A couple of bugs have been fixed, and the manual has been improved.
It is recommended for every user to upgrade to this version.
