Title: The Chemical Origins of Plasma Contraction and Thermalization in CO2 Microwave Discharges Authors: A.W. van de Steeg, L. Vialetto, A.F. Sovelas da Silva, P. Viegas, P. Diomede, M.C.M. van de Sanden, G.J. van Rooij Journal: The Journal of Physical Chemistry Letters Date: 2022-02-11 Description: In this letter first Thomson scattering measurements in pure CO2 plasma were reported. The measurements show a thermalazation of electron temperature and gas temperature occurs with increasing pressure, coinciding with plasma contraction. A 1D model is coupled with these measurements to elucidate the mechanisms behind both phenomena. Thus, it is revealed that associative ionization of radicals plays a crucial role. It connects thermal properties (gas temperature, heat and mass transport) with electon properties. Access rights: Open License: Creative Commons Attribution 4.0 This replication package consists of the raw data used for the creation of each figure, ie measurement data, together with the python scripts used for data treatment. Most raw data is in the form of .spe files. The python library (by D.v.d. Bekerom) calibrate_fiber_pos is always used to read these camera images. The modelling data can be found separately in the publication of L. Vialetto (ref 20 in the Letter).