answer Home › Forums › density functional theory › the Born-Oppenheimer approximation › answer This topic has 0 replies, 1 voice, and was last updated 2 days, 6 hours ago by stephen wienk. Viewing 1 post (of 1 total) Author Posts October 3, 2026 at 12:32 pm #15181 stephen wienkParticipant The BOA is no longer valid when the nuclei are moving to quickly to be neglected. This can be when a solid gets heated close to its melting point. Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In