Evaporative cooling

Microwave shielding enables efficient evaporative cooling of NaK molecules.
Nature 607, 677 (2022)

Hard-collision glory scattering

Unexpected forward scattering in molecular collisions with large amounts of energy transfer.
Nature Chemistry 14, 664 (2022)

Controlling reactions by interference

Chemical reactions between NaLi molecules and Na atoms are controlled using Feshbach resonances.
Science 375, 1006 (2022)

Shielding realized experimentally!

First experimental realization of microwave shielding, using CaF molecules in optical tweezers.
Science 373, 779 (2021)

Interaction engineering

Interactions between molecules can be controlled using microwaves. We show how this gives access to strong resonant dipolar interactions.
Phys. Rev. Lett. 125, 063401 (2020)


Experiments on ultracold KRb molecules quantitatively confirm our theory of collision complex lifetimes and photo-excitation rates.
Nature Physics 16, 1132 (2020)

Collision complexes

Collisions between ultracold molecules lead to loss mediated by formation of complexes. Our new theory quantifies the lifetime of these complexes and indicates their loss could be to due photo-excitation.
Phys. Rev. Lett. 123, 123402 (2019)


Microwaves can be used to engineer repulsive interactions between molecules that can prevent losses while maintaining large elastic cross sections, key to cooling molecules to high phase-space density.
Phys. Rev. Lett. 121, 163401 (2018)


Dr. Tijs Karman

  • 2021-
    Assistant professor, Radboud University Tenured June 2022
  • 2018-2021
    Post-doctoral fellow, ITAMP, Harvard NWO Rubicon grant and ITAMP fellowship
  • 2017-2018
    Post-doc, Durham University, with Jeremy Hutson
  • 2013-2017
    Ph.D., Radboud University, with Gerrit Groenenboom

Computer codes available

Open source computer code is available through gitlab. This currently contains our code for the computation of the density of states and photo-excitation rate of molecule-molecule collision complexes.


Publications in the Theoretical Chemistry database
Publications in Google Scholar

B.Sc. and M.Sc. thesis projects

Please send me a message if you are interested in opportunities for a bachelor's or master's research project in chemistry or physics.

Positions available!

I am looking for Ph.D. students interested in ultracold molecules and theoretical molecular physics. Interested? Send me an email.