this may be a silly question. However, is there a difference between the following sentences (in terms of spelling):
1) Doumo arigatou gozaimashita. 2) Dōmo arigatō gozaimashita.
Is one sentence more correct than the other? I know that they are used for giving thanks (past tense). But I am not sure if "doumo" or "domo" and "arigatou" or "arigatō" are more correct.
Thank you for your help.