Low frequency dynamics of CO/Cu-breakdown of Born-Oppenheimer approximation
- Yale Univ., New Haven, CT (United States)
- Brookhaven National Lab., Upton, NY (United States)
- AT and T Bell Labs., Murray Hill, NJ (United States)
- Exxon Research and Engineering Co., Annandale, NJ (United States)
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)R30{degree} CO/Cu(1ll), c(2 {times} 2) CO/Cu(100) and (1 {times} 2) CO/Cu(l10)], in the 100-2500 cm{sup {minus}1} ({approximately}12.5 {minus} 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 Head-Gordon and Tully, 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 broad-band absorption and dipole-forbidden peak.
- Research Organization:
- Brookhaven National Lab., Upton, NY (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 10116116
- Report Number(s):
- BNL-49777; CONF-9311104-16; ON: DE94005508
- Resource Relation:
- Conference: 40. national symposium of the American Vacuum Society (AVS),Orlando, FL (United States),15-19 Nov 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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