Tuesday, July 30, 2013

1307.7550 (Yulia E. Shchadilova et al.)

Rotation of a single acetylene molecule on Cu(001) by tunneling
electrons in STM
   [PDF]

Yulia E. Shchadilova, Sergei G. Tikhodeev, Magnus Paulsson, Hiromu Ueba
We study the elementary processes behind one of the pioneering works on STM controlled reactions of single molecules [Stipe et al., Phys. Rev. Lett. 81, 1263 (1998)]. Using the Keldysh-Green function approach for the vibrational generation rate in combination with DFT calculations to obtain realistic parameters we reproduce the experimental rotation rate of an acetylene molecule on a Cu(100) surface as a function of bias voltage and tunneling current. This combined approach allows us to identify the reaction coordinate mode of the acetylene rotation and its anharmonic coupling with the C-H stretch mode. We show that three different elementary processes, the excitation of C-H stretch, the overtone ladder climbing of the hindered rotational mode, and the combination band excitation together explain the rotation of the acetylene molecule on Cu(100).
View original: http://arxiv.org/abs/1307.7550

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