Details have been announced for the Metropolitan Opera's 14 performances coming to the Kennedy Center this spring. The company will be here for two weeks this year, twice the length of its visit last season. This means that between April 20 and May 2 there will be two performances each of Verdi's "La Traviata" and Requiem, Puccini's "Manon Lescaut," Mozart's "Don Giovanni," Saint-saens "Samson et Dalila," Kurt Weill's "Mahogonny," and the double bill, "Cavalleria Rusticana" and "I Pagliacci."

The Met's music director, James Levine, will conduct the Puccini, Mozart, Weill and the Requiem, with Thomas Fulton in charge of "Traviata," David Stivender conducting the double bill, and Neeme Jarvi the "Samson."

The two-weeks' run opens on April 20 with "Manon Lescaut," sung by Renata Scotto, Ermanno Mauro, Pablo Elvira, Ara Berberian and Philip Creech. It will be repeated on the 28th with the same cast. The title role in "Don Giovanni" will be sung by James Morris, with Johanna Meier, Carol Neblett, Kathleen Battle, David Rendall, Donald Gramm, John McCurdy and Lenus Carlson filling out the cast at the April 25 matinee and the evening of May 2.

The "Cav" and "Pag" doubleheader will be sung on April 25 and May 1 by Galina Savova, Mauro and Cornell MacNeil in the Mascagni opera. Harry Theyard will sing the Turiddu at the second performance. The "Pagliacci" cast is headed by Patricia Craig on the 25th, with Catherine Malfitano on the 1st, joined by Mauro, MacNeil, Creech and Allan Monk, for whom Carlson will substitute on May 1.

Shirley Verrett will sing Dalila opposite Richard Cassilly, with Louis Quilico, Morley Meredith, and John Macurdy on April 24 and the May 2 matinee. The Weill opera, presented here several seasons ago by the Opera Society of Washington, will be sung on April 22 and 29. The cast includes Teresa Stratas, Lili Chookasian, Cassilly, Ragnar Ulfung, MacNeil and Paul Plishka, with Arturo Sergi and Timothy Jenkins singing in the second performance.

For the Verdi Requiem on April 23 and 30, Levine will have Scotto, Florence Quivar, Giuliano Ciannella and Paul Plishka as soloists, together with the Met chorus and orchestra.