Utilising Quadrupolar Level Crossing Resonance to Gain Important Information of Muon Stopping Sites in TCNQ Charge Transfer Salts

There is much debate about muon stopping sites within materials and in many cases knowing where the muon stops is crucial to understanding the physical properties of different samples. Molecular solids present an interesting array of compounds for both chemists and physicists, however there is little understanding as to how the muon behaves in these materials. We seek to use muon-nuclear quadrupolar level crossing resonance (QLCR) to probe this. Within TCNQ charge transfer salts, one observes a full relaxing asymmetry, that is contrary to the behaviour within neutral TCNQ where one sees a significant muonium fraction. Our work so far has shown that within two different TCNQ charge transfer salts, a 1:1 and 1:2 sample, we are able to observe QLCR peaks that match our predictions. Further work is needed to fully understand these states and allow us to understand these molecular systems.