What is the expiation for someone who falsely swore an oath of divorce, while not being married?

This oath is a Ghamus oath (a false oath sworn knowingly). The majority of scholars believe that it does not require expiation but rather repentance and seeking forgiveness. If the oath was sworn by Allah or one of His attributes, then divorce becomes binding if there is a wife. If the oath was made using the word "divorce" alone, without swearing by Allah, then it is a sin, according to the Prophet, peace and blessings be upon him, who said: "Whoever swears an oath, let him swear by Allah or remain silent." There is disagreement regarding whether divorce occurs through it. If one intended to lie by it, then divorce does not occur through it.