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arXiv · 1312.7113

Isotope effect in acetylene C$_2$H$_2$ and C$_2$D$_2$ rotations on Cu(001)

Yulia E. Shchadilova·Sergei G. Tikhodeev·Magnus Paulsson·Hiromu Ueba
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Abstract

A comprehensive analysis of the elementary processes behind the scanning tunneling microscope controlled rotation of C$_2$H$_2$ and C$_2$D$_2$, isotopologues of a single acetylene molecule adsorbed on the Cu(001) surface is given, with a focus on the isotope effects. With the help of density-functional theory we calculate the vibrational modes of C$_2$H$_2$ and C$_2$D$_2$ on Cu(001) and estimate the anharmonic couplings between them, using a simple strings-on-rods model. The probability of the elementary processes -- non-linear and combination band -- are estimated using the Keldysh diagram technique. This allows us to clarify the main peculiarities and the isotope effects of the C$_2$H$_2$ and C$_2$D$_2$ on Cu(001) rotation, discovered in the pioneering work [Stipe et al., Phys. Rev. Lett. 81, 1263 (1998)], which have not been previously understood.

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Yulia E. Shchadilova, Sergei G. Tikhodeev, Magnus Paulsson, Hiromu Ueba. 2013-12-26. Isotope effect in acetylene C$_2$H$_2$ and C$_2$D$_2$ rotations on Cu(001). https://doi.org/10.1103/physrevb.89.165418

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