Comment on “study of the interaction of a palladium nanocontact with a hydrogen molecule”

Abstract

(i) The authors wrote, “In order to model the for mation of metallic nanocontacts, we used the method of molecular statistics with many particle potentials [13].” Then, the potential used by the authors was pre sented. It is noteworthy that the form of a part of the repulsive interaction potential from the work W. Zhong, Y. Cai, and D. Tomanek, Phys. Rev. B 46, 8099 (1992) cited in the commented work as [13] dif fers from that used in the commented work. As a result, it is unclear how the authors used the parame ters of the potentials from [13]. If the form of the potential was changed after certain mathematical transformations, this problem (as well as the applica bility of the parameters from [13] and the effect of these transformations on the accuracy of the repro duction of the physical phenomenon under study) was not discussed. (ii) From qualitative reasons, it can be assumed that the binding energy for one dimensional nano contacts will be higher than that for the same atoms on a surface. (Although the applicability of this approach to calculate surface configurations can sometimes be doubtful, see, e.g., Phys. Rev. B 61, 2203 (2000).) However, the authors did not present any results of ab initio calculations that can confirm the correctness of the used parameters of the potential for the calcula tions of the properties of the surface configurations and the one dimensional nanocontact. (iii) The so called tight binding approach used in the commented work was developed and used prima rily for the calculations of the properties of metallic nanostructures with fcc lattices. The authors of the commented work did not present the results of test cal culations that confirm the applicability of this approach for the description of H–H bonds.