Reactions of atomic hydrogen and nucleic acid bases with Ge(100) surface

Abstract

Kinetics of H2 (D2) desorption from a Ge(100)-2x1:H (D) surface studied using scanning tunneling microscopy and temperature programmed desorption The kinetics of H2 (D2) desorption from a Ge(100)-2x1:H (D) surface was studied using scanning tunneling microscopy (STM) and temperature programmed desorption (TPD). Inspection of STM images of surfaces at the saturation coverage of H (D) (~ 1.0 ML) revealed a 2x1 monohydride (monodeuteride) phase in which most H (D) atoms were paired on Ge-dimers. By counting the sites of H2 (D2) desorption in STM images taken after desorption of H2 (D2) at temperatures in the range Ts = 500 ? 550 K, the desorption of H2 (D2) was found to follow first order kinetics with an activation energy of Ed = 1.65 ± 0.1 eV (1.65 ± 0.1 eV) and a pre-exponential factor of Vd = (2.7 ± 0.5) x 1013 s-1 ((1.2 ± 0.5) x 1013 s-1). These values of Ed and Vd were used to simulate TPD spectra for the desorption of H2 (D2) from a Ge(100)-2x1:H (D) surface. The simulate