Bjornsson group: Computational molecular chemistry

This is the research group website of the computational molecular chemistry group of Dr. Ragnar Björnsson in the  COMX team at  LCBM of the CEA in Grenoble, France.

Group was previously located at  The Max Planck Institute for Chemical Energy Conversion and at the Science Institute - University of Iceland.


We study all kinds of molecules, from the smallest diatomics to large metalloproteins by a number of different computational chemistry methods: from molecular mechanics (MM), via semiempirical and density functional theory methods to high-accuracy coupled cluster and multiconfigurational methods. A focus is on spectroscopic properties and reactivity of inorganic complexes, computational molecular catalysis, modelling of the condensed phases by QM/MM methods and a special topic of interest is to gain a fundamental electronic-structure level understanding of complex metalloenzymes such as nitrogenase, hydrogenases and CO dehydrogenases.

More recently we have started to develop our own program ASH: a multi-scale, multi-theory modelling program. 

Inquires and open positions

Contact Ragnar: ragnar.bjornsson(at)




Ragnar is co-chairing QBIC-VI, the sixth conference on Quantum Bio-Inorganic Chemistry, held in Warsaw, Poland from 29 Aug to 1 Sep 2023! Come join us in Warsaw!

December 2021

Ragnar has relocated to CEA Grenoble for a permanent CEA researcher position at the LCBM, CEA Grenoble

January 2021

Ragnar was awarded the 2021 QBIC award by the Quantum BioInorganic Chemistry Society.

May 2020

PCCP cover graphic for the collaborative article with Filipe Ferreira da Silva and  Oddur Ingólfsson.

April 2020

The Chemical Reviews article on The Spectroscopy of Nitrogenases from the department of Inorganic Spectroscopy is out!

January 2020

Our QM/MM work on nitrogenases is highlighted on the Chemshell website.

October 2019

Albert's paper on the E4 state of FeMoco and dinitrogen binding is accepted in Chemical Science!

September 2019

A joint EXAFS-QM/MM study from the us and Serena DeBeer and coworkers, characterizing the E1 of FeMoco is accepted in Chemical Science!

January 2019

Albert's paper on the mechanisms of substrate reductions in [MoFe3S4] cubanes is accepted in Inorganic Chemistry:

December 2018

Cody's paper on an explicit solvation approach to redox potentials is accepted in JCTC:

May 2018

Barði and Albert defended their M.Sc. theses on May 17th and May 18th at the University of Iceland.

"Theoretical mechanistic studies of nitrogenase and model compounds"

"QM/MM studies of molybdenum and vanadium nitrogenase"

Barði and Albert's paper on the nature of ligand X in a vanadium nitrogenase crystal structure is accepted in Chemical Communications.

QM/MM calculations reveal a bridging hydroxo group in a vanadium nitrogenase crystal structure

April 2018

Group is delocalized! Ragnar has relocated to the Max Planck Institute for Chemical Energy Conversion to take up a position as group leader. 

January 2018

Cody defended his M.Sc. thesis, titled "A black-box explicit solvation protocol for calculation of redox potentials"  on Monday 22nd of January. Congratulations!

October 2017

Barði's QM/MM paper is now online!:

 QM/MM Study of the Nitrogenase MoFe Protein Resting State: Broken-Symmetry States, Protonation States, and QM Region Convergence in the FeMoco Active Site

Bardi Benediktsson and Ragnar Bjornsson*, Inorg. Chem. 2017, Article online.Free e-print Link 

June 2016

Heiðar and Albert finish their B.Sc. theses. Congratulations! They will work in the group for the summer.

Arnar Hafliðason also joins the group for this summer. Arnar will be working with the molecular crystal QM/MM code.

April 2016

Barði Benediktsson rejoins the group. Barði will be working on the nitrogenase project this summer and then begin his M.Sc. in the fall.

March 2016

Group is awarded a 280K Euro grant from the Icelandic Research Fund to continue research on the metalloprotein nitrogenase.

Spring 2016

Albert Þ. Þórhallsson and Heiðar M. Aðalsteinsson, B.Sc. students in chemistry, do their B.Sc. projects in the group this semester.

Fall 2015:

Cody Sterling (M.Sc. student) joins the group. Cody will be working on QM/MM solvation.

Summer 2015

Albert and Heiðar (undergraduate students) join the group for the summer.

February 2015

ESRF (European Synchrotron Radiation Facility) Highlights 2014 issue is out. 

Contains a mini-article on the Mo(III) Chemical Science article and FeMoco made the cover.

Identification of a spin-coupled Mo(III) in the Nitrogenase Iron-Molybdenum Cofactor

R. Bjornsson, F. A. Lima, T. Weyhermüller, T. Spatzal, O. Einsle, E. Bill, F. Neese and S. DeBeer, Chemical Science, 2014, 5, 3096-3103.

January 2015

New FeMoco mini-review published in JBIC!

The discovery of Mo(III) in FeMoco: reuniting enzyme and model chemistry

R. Bjornsson*, F. Neese, R. R. Schrock, O. Einsle, S. DeBeer*, J. Biol. Inorg. Chem. 2015, online article (invited review)

Barði Benediktsson B.Sc. biochemistry student joins the group.