The plasma decomposition studies of bis(cyclopentadienyl) Fe (II), (FeCp2) were performed in a cylindrical (inner diameter = 142 mm and height = 300 mm) stainless-steel vacuum chamber, described in detail in our previous study. A titanium hollow cathode (inner diameter = 6 mm, length = 53 mm) was positioned in the lid of the vacuum chamber. The chamber was pumped down to a background pressure of 6 Pa, achieved by a vacuum pump. Ar (99.999 %, Linde gas AB) with a flow of 140 SCCM was used for the plasma generation in all measurements, resulting in a total pressure of 30 Pa. For all measurements, a plasma power of 100 W was used.