Does a person's uttering of the word of divorce while trying to recall a previous divorce formula uttered by him, constitute a new divorce, especially since he was alone and his wife was absent?

Divorce does not occur in this case, nor does it occur in the matter of narrating a divorce or uttering it for the purpose of teaching or issuing a fatwa. If the condition upon which the divorce was contingent did not materialize, then nothing is incumbent upon you. However, if it did materialize, then the divorce is effective according to the majority of scholars, whether you intended the divorce or merely a threat. Reinstating the wife is valid through an action such as intercourse, provided that this divorce does not complete the third one. Sheikh al-Islam Ibn Taymiyyah is of the view that the divorce is not binding upon you if you did not intend it, but an expiation for a broken oath (kaffarat yamin) becomes incumbent upon you.