%0 Journal Article
%T Ultrafast Vibrational Dynamics of CO Ligands on RuTPP/Cu(110) under Photodesorption Conditions
%J Surfaces | An Open Access Journal from MDPI
%D 2019
%R https://doi.org/10.3390/surfaces2010010
%X We have studied CO coordinated to ruthenium tetraphenylporphyrin (RuTPP)/Cu(110) and directly adsorbed to Cu(110), using femtosecond pump-sum frequency probe spectroscopy, to alter the degree of electron-vibration coupling between the metal substrate and CO. We observe the facile femtosecond laser-induced desorption of CO from RuTPP/Cu(110), but not from Cu(110). A change in the vibrational transients, in the first few picoseconds, from a red- to blue-shift of the C¨CO stretching vibration under photodesorption conditions, was also observed. This drastic change can be explained, if the cause of the C¨CO frequency redshift of Cu(110) is not the usually-assumed anharmonic coupling to low frequency vibrational modes, but a charge transfer from hot electrons to the CO 2¦Ð* state. This antibonding state shifts to higher energies on RuTPP, removing the C¨CO redshift and, instead, reveals a blueshift, predicted to arise from electron-mediated coupling between the coherently excited internal stretch and low frequency modes in the system. View Full-Tex
%U https://www.mdpi.com/2571-9637/2/1/10