"Every quartet has a different chemistry," says cellist David Finckel of the Emerson String Quartet. If a grueling touring and recording schedule is any indication, it seems to be the right chemistry for them.

The quartet, appearing Thursday at the Kennedy Center Concert Hall as part of the Lincoln Center's Mostly Mozart Festival, has performed more than 100 concerts worldwide for each of the last five years and has resident ensemble status at four institutions, including the Smithsonian and the Chamber Music Society of the Lincoln Center. "It's somewhat of a battle to live a seminormal, healthy life and deal with the stress of public performance," says Finckel.

The group, made up of Finckel, violist Lawrence Dutton and violinists Eugene Drucker and Philip Setzer, formed 10 years ago at New York's Juilliard school. Finckel attributes the ensemble's continuing vitality to the musicians' strengths as individual players. Competition among string quartets today means that "each person needs to have some background as a soloist," says Finckel.

While the group recently signed a recording contract with Deutsche Grammophon, Finckel remains enthusiastic about live performance. "I hope the audience is involved in the same kind of struggle that we are with the music as we're playing," he says.

For tickets, call 857-0900; for information, call 254-3776.