# Do the U values affect structure optimization with the DFT+U simulation to optimize crystal structure?

I am trying to do structure optimization of TiO2, since titanium is a transition metal, I need to use DFT+U to simulate the right band structure, but the electronic band structure would also affect the force on atoms, so does this mean that I need to use DFT+U model during the structure optimization stage? How important would the inclusion of U values be?

• Choosing U values, When to use, Resources. I don't know enough about U corrections to know if the 2nd link applies also to geometry optimizations, but I suspect it would.
– Tyberius
Jan 18 at 18:55
• Not obvious from how you phrased your question if your work already accounts for this (elsewhere, there is an implicit none), be aware about polymorphism of $\ce{TiO2}$, e.g., rutile, anatase, brookite. Jan 19 at 9:04
• Since U is about electron localization, the answer largely depend on the specific structure / charge, presence of polarons etc you want to optimize. This is also a question that often can be answered or have an educated guess based on existing literature. TiO2 is a very well researched material (all the common polymorphs), why do not you do a little research?
– Greg
Jan 20 at 6:21