Regular Article

Reactive molecular dynamics simulations of organometallic compound W(CO)₆ fragmentation^⋆,,^⋆⋆

¹ MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main, Germany
² Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
³ On leave from Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia

^a e-mail: devera@mbnexplorer.com

Received: 14 May 2019
Received in final form: 25 July 2019
Published online: 22 October 2019

Abstract

Irradiation- and collision-induced fragmentation studies provide information about geometry, electronic properties and interactions between structural units of various molecular systems. Such knowledge brings insights into irradiation-driven chemistry of molecular systems which is exploited in different technological applications. An accurate atomistic-level simulation of irradiation-driven chemistry requires reliable models of molecular fragmentation which can be verified against mass spectrometry experiments. In this work fragmentation of a tungsten hexacarbonyl, W(CO)₆, molecule is studied by means of reactive molecular dynamics simulations. The quantitatively correct fragmentation picture including different fragmentation channels is reproduced. We show that distribution of the deposited energy over all degrees of freedom of the parent molecule leads to thermal evaporation of CO groups and the formation of W(CO)_n⁺ (n = 0 – 5) fragments. Another type of fragments, WC(CO)_n⁺ (n = 0 – 4), is produced due to cleavage of a C–O bond as a result of localized energy deposition. Calculated fragment appearance energies are in good agreement with experimental data. These fragmentation mechanisms have a general physical nature and should take place in radiation-induced fragmentation of different molecular and biomolecular systems.