TY - JOUR AU - Ibach, Harald TI - Quantum motion of hydrogen on Ni(100) surfaces JO - Physical review / B VL - 102 IS - 16 SN - 2469-9950 CY - Woodbury, NY PB - Inst. M1 - FZJ-2020-04535 SP - 165405 PY - 2020 AB - Vibration modes of hydrogen atoms on Ni(100) are studied. The number of observed energy losses as well as their full width at half maximum (FWHM) are incompatible with the classical model of localized vibrations. Number and energy of modes agree, however, well with a previously published quantum-mechanical treatment of the motion of hydrogen in the periodic surface potential of Ni(100). For the dilute surface phase of hydrogen, the FWHM is a factor of 4 larger than expected from the dispersion of the bands. The effect is attributed to rapid tunneling of vibrationally excited hydrogen into empty neighboring sites. LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000576600700007 DO - DOI:10.1103/PhysRevB.102.165405 UR - https://juser.fz-juelich.de/record/887943 ER -