It hasn't been a good year for Rep. Frank Thompson Jr. (D-N.J.). He was indicted and convicted of bribery in the FBI's Abscam undercover investigation and defeated at the polls after 13 terms in Congress.

But he should find some solace in the estimated $48,530-a-year government pension he'll soon start receiving. And his felony conviction is no bar to receiving every cent he's due.

House officials said even a crime against the office, like bribery, does not disqualify a member from getting his generous monthly checks. Federal law lists only crimes against the nation, such as treason or sabotage, as reason enough to lose an annuity.

Thus Thompson and the other House members convicted so far in Abscam and defeated in their reelection bids last month will take a little something with them when they close their offices.

Officials at the House sergeant-at-arms office, which computes the pensions, decline to say specifically how much each departing member will get. But computations based on their retirement formula show Thompson probably will get the maximum allowed -- 80 percent of his top salary of $60,662 -- because of his 34 years of government service. This includes eight in the military as well as 26 in Congress, according to a Thompson aide.

Rep. John M. Murphy (D-N.Y.), who was acquitted of bribery but convicted of other charges in his trial with Thompson, should get about $42,058 a year -- based on his 18 years in the House and 12 years in the Army as a West Point graduate and decorated war hero.

The basic pension formula multiplies the average of a retiree's three highest years' salary times the number of years of government service times 2 1/2 percent. Participants contribute 8 percent of their pay to the plan and Uncle Sam's taxpayers match it. The participants are eligible for benefits, and future cost-of-living increases, after five years of service.

Former representative John W. Jenrette (D-S.C.), who resigned from Congress after his bribery conviction last month, and Rep. Richard Kelly (R-Fla.), who is on trial on separate Abscam bribery charges, each will get about $8,824 a year for their six years in the House. They can't start collecting until age 62, however.

Former representative Michael (Ozzie) Myers (D-Pa.), the first member expelled from Congress in 100 years after his Abscam bribery conviction, won't get any government check because he served only two terms. He, like the others, is appealing his conviction on grounds the FBI and Justice Department overstepped constitutional bounds in pursuing the undercover operation.

Former representative Charles C. Diggs Jr. (D-Mich.), who resigned after his payroll kickback conviction in 1978, reportedly is receiving a $38,232-a-year pension in prison. He had agreed to pay back to the Treasury, in a sort of payroll deduction, the $40,000 he took. But when he resigned and began serving his term in July, the deduction was not transferred and taken from his pension checks, according to a Justice official.

House officials said they aren't sure how much Diggs still owes.

A Justice official said recently that the department is planning to file civil suits against the congressmen convicted in Abscam to recover the bribe money they took.