The objective of this interdisciplinary project is to quantitatively interpret the unexpected ALMA detection of ro-vibrationally excited water molecules in evolved stars from a theoretical, experimental and astrophysical point of view. To this end, the collisions of ro-vibrationally excited water molecules with H2, H, He and the electrons will be studied by taking for the first time into account, the coupling between the bending and rotation modes of water. In order to validate the calculations experimentally, the Bordeaux crossed-beam machine will be adapted to generate a supersonic jet of vibrationally excited water molecules. The third pillar of the project dedicated to the modeling of the ALMA data will integrate the new collision rates into an advanced radiative transfer code. The new experimental and theoretical results produced in the course of the project to model our star observations will also be applicable to the general interstellar medium.