Ab initio calculations about intrinsic point defects and He in W

We have used ab initio calculations in the framework of the density functional theory to determine the properties of the self-interstitial atom, the vacancy, vacancy clusters and He in tungsten. The most stable configuration for the self-interstitial atom is the 〈1 1 1〉 dumbbell. The divacancy is not stable and a strong repulsion is observed especially in second nearest neighbour position. The most stable configuration for interstitial He is in tetrahedral position. The interactions of He atoms with a vacancy are found to be in very good agreement with the experimental data.