New approach of model-free analysis for quasi-elastic neutron scattering and applications for liquid water

Kikuchi, Tatsuya  ; Nakajima, Kenji  ; Kawamura, Seiko   ; Inamura, Yasuhiro  ; Yamamuro, Osamu*; Kofu, Maiko*   

In generally so far, analysis of quasi-elastic neutron scattering spectra needs some mathematical models in its process, and hence the obtained result is a model dependent. Model-dependent analysis may lead misunderstandings caused by inappropriate initial models or may miss the unexpected phenomenon. Therefore, the alternative approach of analysis without any specific model is desired. In this context, we are trying to develop new method, which does not require any specific initial models. In this new approach, we can obtain new quantity, by using maximum entropy method (MEM). Our new approach was applied on liquid water. Obtained shows diffusion process in this system consist of three components: a slow motion, a fast motion and an intermediate motion between two. As it has been thought, the slow component is a translational motion and the fast component is a rotational motion. In contrast, the intermediate motion is discovered for the first time.