Molcas is an ab initio quantum chemistry software package developed by scientists for scientists. The page currently refers to Molcas 8.6, with version 8.8 planned for release in summer 2026. Its core positioning is not as a general-purpose black-box computational tool, but as software for tackling complex electronic structures in molecules composed of most elements in the periodic table, with particular emphasis on multiconfigurational methods and highly degenerate states.
In terms of functionality, Molcas explicitly lists methods such as SCF/DFT, CASSCF/RASSCF, and CASPT2/RASPT2, making it suitable for computational chemistry research that requires fine-grained control over electronic structure models. The software emphasizes being fast, accurate, and robust, while also stating that users should be trained quantum chemists who understand the applicability and accuracy limits of different quantum chemistry models. On the platform side, the page provides Linux64+MKL binary installation instructions, while the FAQ covers Linux, Mac OS, MS Windows, optimized BLAS compilation, and related topics. No API/SDK information is provided; the main interaction model is closer to local command-line research software, for example running different Molcas/OpenMolcas versions via molcas -use=ALIAS input.
Molcas is closely related to OpenMolcas: Molcas is based on stable versions of OpenMolcas, distributed by Lund University, uses a time-limited license, and includes support and validated releases. OpenMolcas, by contrast, is the LGPL-licensed developer branch, with integrity verified through automated testing. In terms of documentation, the site provides FAQ, README, Features, Methods, Applications, and Showcase sections, and also organizes regular MOLCAS workshops. Topics include installation, payment, patches, bug reports, active-space selection, and other specialist subjects. The information density is high, though the overall style is relatively traditional.
Molcas uses a paid licensing model. The example on the page shows a 3-year academic license priced at 2500 EUR; credit-card payments must be settled in SEK, with the example amount listed as 27000 SEK. Payment can be made by bank transfer or Visa/Mastercard, but the process requires an order form, signed copyright and license agreements, and invoice handling through Lund University, making the workflow relatively heavyweight. The page also notes that pricing and licensing policies will be adjusted in 2026.
Its strengths are clear capabilities in multiconfigurational methods, validated releases, support, and workshops, making it suitable for universities, research institutes, and computational chemistry teams. Its drawbacks are a steep learning curve, the fact that it is not a black-box tool, and a relatively cumbersome licensing and payment process. Modern developer-tool conveniences such as APIs, cloud services, or one-click subscriptions are not evident.
The page does not provide information about availability, mirrors, or payment accessibility for mainland China, so access from China is unknown. If access or payment is restricted, OpenMolcas may be worth evaluating first as an open-source alternative.
β This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on molcas.org official site.
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