Momentum distribution (IMAGE) Forschungszentrum Juelich Caption The experimental momentum distribution of photoelectrons from pure copper and from para-quinquephenyl molecules adsorbed on copper (left) and the theoretical momentum distribution from free molecules and adsorbed molecules on copper (right). Credit Forschungszentrum Jülich / X.Yang, S. Soubatch; Graz University / P. Puschnig Usage Restrictions Editorial usage permitted with credit to source. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.