Two of choreographer Gerald Arpino's visions of contemporary youth were on display last night at the Kennedy Center Opera House. "Trinity," the Joffrey Ballet's 1970 celebration of the Flower Child generation, complete with peace candles, closed the program; "Light Rain," the new, 1981 version of today's youth, opened it.

In "Trinity," the dancing bursts with energy, while the dancers hold hands, make eye contact with each other, smile at the audience. Led by Mark Goldweber and a charming newcomer named Edward Morgan, it was the decided hit of the evening. "Light Rain" is more sour. No one smiles, dancers rarely touch, the central pas de deux is an expression of self-absorbed ardor. The ballet is full of pseudo-orientalisms--some poses look as though they'd be at home in a Soviet version of "Legend of Love"--and the dancers move in their own orbits, their frantically shaking hands often the only evidence of youthful energy.

Douglas Adams' and Russ Gauthier's music for "Light Rain" is in the trancelike, repetitive mode and breaks no new ground. Some of Arpino's choreography, however, particularly in the solos for Leslie Carothers, is intriguing. In "Light Rain," unlike other Arpino works on view this season, the legs have more to do than leap. James Canfield, who partnered Carothers and danced his brief solo ferociously, was excellent.

Laura Dean is a modern dance choreographer, but her "Night," set to her own arresting score, is classical in construction. Even in last night's rocky performance her skill in assembling patterns was clear, with repeated steps building logically and inexorably to the dance's conclusion.

"Deuce Coupe II," Twyla Tharp's twitching dance for street-wise beach bums, completed the program.