Related Experiment Video
Updated: May 29, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
An efficient parallel algorithm for the calculation of unrestricted canonical MP2 energies
Jon Baker1, Krzysztof Wolinski
1Parallel Quantum Solutions, Fayetteville, Arkansas 72703, USA. baker@pqs-chem.com.
Abstract:
We present details of our efficient implementation of full accuracy unrestricted open-shell second-order canonical Møller-Plesset (MP2) energies, both serial and parallel. The algorithm is based on our previous restricted closed-shell MP2 code using the Saebo-Almlöf direct integral transformation. Depending on system details, UMP2 energies take from less than 1.5 to about 3.0 times as long as a closed-shell RMP2 energy on a similar system using the same algorithm. Several examples are given including timings for some large stable radicals with 90+ atoms and over 3600 basis functions.
More Related Videos
Related Concept Videos
Mechanistic Models: Compartment Models in Algorithms for Numerical Problem Solving
In individual population analyses, different algorithms are employed, such as Cauchy's method, which uses a...
Calculating Standard Free Energy Changes
Extraction: Partition and Distribution Coefficients
For extracting a solute from an aqueous phase into an organic...
Hybridization of Atomic Orbitals II
π Molecular Orbitals of the Allyl Cation and Anion
Arrhenius Plots
The Arrhenius equation can be used to...

