(a) Except as stated in paragraph (d), a lawyer shall not represent anyone in connection with a matter in which the lawyer participated personally and substantially as a judge or other adjudicative officer or law clerk to such a person or as an arbitrator, mediator or other third-party neutral.
(b) A lawyer shall not negotiate for employment with any person who is involved as a party or as lawyer for a party in a matter in which the lawyer is participating personally and substantially as a judge or other adjudicative officer or as an arbitrator, mediator or other third-party neutral. A lawyer serving as a law clerk to a judge or other adjudicative officer may negotiate for employment with a party or lawyer involved in a matter in which the clerk is participating personally and su