Low-frequency dynamics of CO/Cu breakdown of Born--Oppenheimer approximation
Abstract
Synchrotron infrared studies of adsorbates on surfaces offer the possibility of probing low-frequency vibrational modes and dynamics at high resolution (1 cm[sup [minus]1], 125 [mu]eV). Extensive experiments have been performed for ordered submonolayers of CO on low index Cu surfaces [([radical]3[times][radical]3)[ital R]30[degree] CO/Cu(111), [ital c](2[times]2) CO/Cu(100) and (1[times]2) CO/Cu(110)], in the 100--2500 cm[sup [minus]1] ([similar to]12.5--312.5 meV) range. These are the first IR experiments to directly probe the adsorbate-substrate vibrations for this system. In addition, however, several surprising features are observed including the dipole-forbidden hindered rotation and an unexpected broadband absorption. Two theories have been motivated by this work, and will be compared to our experimental results. The first theory is a cluster calculation by Tully, Gomez, and Head-Gordon, which takes into account the breakdown of the Born--Oppenheimer approximation and predicts lifetimes and frequencies of the vibrational modes for CO/Cu(100). Another Drude-based theory, proposed by Persson, considers the coupling of the conduction electron current to the vibrations of the adsorbates, accounting for the observation of both the broadband absorption and dipole-forbidden peak.
- Authors:
-
- Yale University, New Haven, Connecticut 06520 (United States) NSLS, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- AT T Bell Labs, Murray Hill, New Jersey 07974 (United States)
- EXXON Research and Engineering, Annandale, New Jersey 08801 (United States)
- NSLS, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Publication Date:
- OSTI Identifier:
- 7084995
- DOE Contract Number:
- AC02-76CH00016
- Resource Type:
- Journal Article
- Journal Name:
- Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)
- Additional Journal Information:
- Journal Volume: 12:4; Journal ID: ISSN 0734-2101
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; CARBON MONOXIDE; ADSORPTION; COPPER; SORPTIVE PROPERTIES; ABSORPTION SPECTRA; BORN-OPPENHEIMER APPROXIMATION; INFRARED RADIATION; SYNCHROTRON RADIATION; VIBRATIONAL STATES; BREMSSTRAHLUNG; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; ELECTROMAGNETIC RADIATION; ELEMENTS; ENERGY LEVELS; EXCITED STATES; METALS; OXIDES; OXYGEN COMPOUNDS; RADIATIONS; SORPTION; SPECTRA; SURFACE PROPERTIES; TRANSITION ELEMENTS; 360606* - Other Materials- Physical Properties- (1992-)
Citation Formats
Hirschmugl, C J, Chabal, Y J, Hoffmann, F M, and Williams, G P. Low-frequency dynamics of CO/Cu breakdown of Born--Oppenheimer approximation. United States: N. p., 1994.
Web. doi:10.1116/1.579120.
Hirschmugl, C J, Chabal, Y J, Hoffmann, F M, & Williams, G P. Low-frequency dynamics of CO/Cu breakdown of Born--Oppenheimer approximation. United States. https://doi.org/10.1116/1.579120
Hirschmugl, C J, Chabal, Y J, Hoffmann, F M, and Williams, G P. 1994.
"Low-frequency dynamics of CO/Cu breakdown of Born--Oppenheimer approximation". United States. https://doi.org/10.1116/1.579120.
@article{osti_7084995,
title = {Low-frequency dynamics of CO/Cu breakdown of Born--Oppenheimer approximation},
author = {Hirschmugl, C J and Chabal, Y J and Hoffmann, F M and Williams, G P},
abstractNote = {Synchrotron infrared studies of adsorbates on surfaces offer the possibility of probing low-frequency vibrational modes and dynamics at high resolution (1 cm[sup [minus]1], 125 [mu]eV). Extensive experiments have been performed for ordered submonolayers of CO on low index Cu surfaces [([radical]3[times][radical]3)[ital R]30[degree] CO/Cu(111), [ital c](2[times]2) CO/Cu(100) and (1[times]2) CO/Cu(110)], in the 100--2500 cm[sup [minus]1] ([similar to]12.5--312.5 meV) range. These are the first IR experiments to directly probe the adsorbate-substrate vibrations for this system. In addition, however, several surprising features are observed including the dipole-forbidden hindered rotation and an unexpected broadband absorption. Two theories have been motivated by this work, and will be compared to our experimental results. The first theory is a cluster calculation by Tully, Gomez, and Head-Gordon, which takes into account the breakdown of the Born--Oppenheimer approximation and predicts lifetimes and frequencies of the vibrational modes for CO/Cu(100). Another Drude-based theory, proposed by Persson, considers the coupling of the conduction electron current to the vibrations of the adsorbates, accounting for the observation of both the broadband absorption and dipole-forbidden peak.},
doi = {10.1116/1.579120},
url = {https://www.osti.gov/biblio/7084995},
journal = {Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)},
issn = {0734-2101},
number = ,
volume = 12:4,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 1994},
month = {Fri Jul 01 00:00:00 EDT 1994}
}