Tha remarkable assortment of people and ideas that Mussorgsky gathered into his Pictures At An Exhibition-drawing them from the paintings of his friend, Victor Hartmann-is ideally suited to Lazar Berman's style of playing.

Occupying the second half of last night's Kennedy Center concert the Mussorgsky found the famous Soviet pianist doing the best playing of the evening. With a strong feeling of personal identification obvious throughout. Berman demonstrated a feathery touch of perfect weight, mixing it with a ghostly, hushed sound for the Old Castle and vast sonorities for the larger episodes. His phrasing took on a plasticity that lent variety to the procession, and he found ways to suggest both the humorous and the grotesque in the subjects at hand.

His wide palette of sounds at times took on a chiming beauty and there were some dazzling staccati. Finally, for the Great Gate at Kiev, something like brute force was applied, and the playing came very close to just plain messy.

Before the intermission, Berman sounded out of his element in Schuman's difficult F Sharp Minor Sonata. Few pianists have been able to answer the questions of form and content that make this music such a challenge. Except for the exquisite aria, Berman shed no light on the problemss.

In three Chopin Polonaises-in C Sharp Minor, F Sharp Minor, and the big one in A Flat-he put out a large rushing from episode to episode without having established either mood or any sustained line. Essentials were passed up with little or no notice. His is a peculiar and unsatifying kind of Chopin.