Quantemol-EC (QEC) is a new-generation, highly-automated software package designed to calculate electron-molecule scattering cross sections. The calculations are facilitated by a convenient graphical user interface, that allows users to enter their desired calculation settings and parameters. The cross sections are calculated using both the Molpro quantum chemistry package, as well the UKRmol+ suite of molecular R-matrix codes.

QEC thereby offers a synergy between these two sophisticated quantum chemistry tools, packaged in a remarkable user-friendly interface.



QEC distinctive improvements and functionalities feature:

  • Automatic generation of configurations
  • Automatic detection of symmetry
  • Automatic handling of degenerate states
  • More accurate ionisation cross section calculations
  • Storage of results in a directory labelled with the main calculation parameters (e.g. basis set used, R-matrix sphere size).
  • Display of the final results at the end of the calculation
  • Access to the most recent set of executables for the UKRmol+ molecular R-matrix suite of codes
  • Dissociative recombination estimations
  • Non-resonant vibrational excitations for ions and neutrals
  • Effective core potentials for ionisation cross sections

Read more about the software in Quantemol Electron Collisions (QEC): An Enhanced Expert System for Performing Electron Molecule Collision Calculations Using the R-matrix Method. Cooper, B.; Tudorovskaya, M.; Mohr, S.; O’Hare, A.; Hanicinec, M.; Dzarasova, A.; Gorfinkiel, J.; Benda, J.; Masin, Z.; Al-Refaie, A.; Knowles, P.; Tennyson, J.

“The speed with which you provided me a trial of QEC is greatly appreciated. I am very impressed with the software and plan to purchase it very soon.”

Dr Paul Adamson
Naval Research Laboratory , USA

What does the Quantemol-EC do?

Calculates a variety of observables for electron molecule collisions including:

  • Zero – high electron energy extension for all cross sections **
  • Elastic cross-sections
  • Electronic excitation cross-sections
  • Super-elastic/ Quenching/De-excitation cross-sections
  • Electron impact dissociation (subject to the target molecule’s details and customer support availability)
  • Scattering reaction rate
  • Arrhenius parameters for reaction rates
  • Resonance parameters
  • Estimate dissociative electron attachment**
  • Differential cross-sections
  • Momentum transfer cross-sections
  • Electron impact ionisation at all energies**
  • Rotational excitation cross-sections
  • Vibrational excitation cross sections

** features not present in standard R-matrix codes

What are the key advantages of Quantemol-EC?


  • Unique data can be calculated for various molecules and ions which cannot be obtained otherwise experimentally or by other methods
  • The expert system is an umbrella environment covering different calculation methods (R-matrix, SCOP, BEf etc) and delivering results for all energy regions with only one input set up required for a particular molecule.
  • Only robust and validated methods are used to obtain results
  • Exceptionally easy to use interface to set up calculations, view the results and export the data (see our tutorial here)
  • Results are presented in a flexible, user-friendly form and assistance provided for easy conversion to the publication format
  • Proactive support is available from the experts to assist users with any difficulties they may have when running their calculations.
  • OpenMP parallelism speeds up calculations.
  • QEC includes a large suite of molecular examples (currently ~10) and the user can get started immediately.

What range of problems can be tackled with Quantemol-EC?


  • Closed shell molecules
  • Open shell molecules, radicals
  • Neutral and positively charged species
  • Large molecules (up to 25 atoms, preferably lighter than Ar and a subject of RAM available on your workstation)

Underlying Code Development

UKRmol+ is developed by a group of academic researchers who are members of the UK-AMOR consortium and available for download here:

Inner region codes including GTOLib: https://zenodo.org/record/2630496#.XXZkWZwo8eM
Outer region codes: https://zenodo.org/record/3371124#.XXZkoZwo8eM

Inner region codes, including the GBTOlib library: https://zenodo.org/record/3371125
Outer region codes: https://zenodo.org/record/3452068

Read more about the code in the recent publication:

UKRmol+: A suite for modelling of electronic processes in molecules interacting with electrons, positrons and photons using the R-matrix method“, Z. Masin, J. Benda, J. Gorfinkiel, A. Harvey, J. Tennyson.

Vibrational Excitation/Dissociative recombination

Dissociative Recombination of Highly Symmetric Polyatomic Ions
N. Douguet, A.Orel, C Greene, and V. Kokoouline, Phys. Rev. Lett. 108, 023202 (2012)

Theoretical study of dissociative recombination and vibrational excitation of the BF2+ ion by an electron impact
V. Kokoouline, M. Ayouz, J. Z. Mezei, K. Hassouni and I. Schneider, Plasma Sources Science and Technology, Volume 27, Number 11 (2018)

Dissociative recombination of CH2NH2+: a crucial link with interstellar methanimine and Titan ammonia
C H Yuen, M A Ayouz, N Balucani, C Ceccarelli, I F Schneider, V Kokoouline, RAS, Volume 484, Issue 1, (2019)

Dissociative electron recombination of NH2CHOH+ and implications for interstellar formamide abundance
M A Ayouz, C H Yuen, N Balucani, C Ceccarelli, I F Schneider, V Kokoouline, Monthly Notices of the Royal Astronomical Society, Volume 490, Issue 1, (2019)

Quantemol-EC Free trial request form:

The free trial version requires a Molpro licence. You can acquire a molpro free trial HERE. For any further queries please contact us at support@quantemol.com.

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