Real-Time Observation of Surface Bond Breaking with an X-ray Laser.

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Bibliographic Details
Title:	Real-Time Observation of Surface Bond Breaking with an X-ray Laser.
Authors:	Dell'Angela, M., Anniyev, T., Beye, M., Coffee, R., Föhlisch, A., Gladh, J., Katayama, T., Kaya, S., Krupin, O., LaRue, J., Møgelhøj, A., Nordlund, D., Nørskov, J. K., Öberg, H., Ogasawara, H., Öström, H., Pettersson, L. G. M., Schlotter, W. F., Sellberg, J. A., Sorgenfrei, F.
Source:	Science (pre-March 2025). 3/15/2013, Vol. 339 Issue 6125, p1302-1305. 4p.
Subjects:	X-ray lasers, Carbon monoxide, Chemisorption, Electronic structure, Femtosecond lasers, Intermolecular forces, Free energy (Thermodynamics), Density functional theory, Van der Waals forces
Abstract:	We used the Linac Coherent Light Source free-electron x-ray laser to probe the electronic structure of CO molecules as their chemisorption state on Ru(0001) changes upon exciting the substrate by using a femtosecond optical laser pulse. We observed electronic structure changes that are consistent with a weakening of the CO interaction with the substrate but without notable desorption. A large fraction of the molecules (30%) was trapped in a transient precursor state that would precede desorption. We calculated the free energy of the molecule as a function of the desorption reaction coordinate using density functional theory, including van der Waals interactions. Two distinct adsorption wells--chemisorbed and precursor state separated by an entropy barrier--explain the anomalously high prefactors often observed in desorption of molecules from metals. [ABSTRACT FROM AUTHOR]
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Database:	Psychology and Behavioral Sciences Collection

Description
Abstract:	We used the Linac Coherent Light Source free-electron x-ray laser to probe the electronic structure of CO molecules as their chemisorption state on Ru(0001) changes upon exciting the substrate by using a femtosecond optical laser pulse. We observed electronic structure changes that are consistent with a weakening of the CO interaction with the substrate but without notable desorption. A large fraction of the molecules (30%) was trapped in a transient precursor state that would precede desorption. We calculated the free energy of the molecule as a function of the desorption reaction coordinate using density functional theory, including van der Waals interactions. Two distinct adsorption wells--chemisorbed and precursor state separated by an entropy barrier--explain the anomalously high prefactors often observed in desorption of molecules from metals. [ABSTRACT FROM AUTHOR]
ISSN:	00368075
DOI:	10.1126/science.1231711