Weekday matinees, particularly those devoted to top-flight chamber ensembles, are not exactly common in the Washington music scene. But judging by the large, attentive and enthusiastic audience on hand Friday to hear the Momenta String Quartet at the National Gallery of Art’s West Building, more ensembles should consider them.

The members of Momenta — violinists Emilie-Anne Gendron and Adda Kridler, violist Stephanie Griffin and cellist Michael Haas — are sterling musicians. With more than 80 premieres to the quartet’s credit, Momenta’s commitment to new music is well established.

The demanding program, played without intermission, began with Philip Glass’s String Quartet No. 2 (“Company”), a less-than-familiar work by probably the best known of the American minimalist composers. This performance created an enveloping mystical aura from which melancholy lines, subtle pulses and delicate colors emerged with an almost palpable and sensual beauty.

Glass completed his quartet in 1983, the year the other American composer on the program, Eric Nathan, was born. Nathan’s “Multitude, Solitude” was commissioned by Momenta, which played its premiere in 2013.

Inspired by walks along the beach in Britain’s East Anglia, sounds of the North Sea and seagulls overhead may be heard among the textures of this richly evocative piece. Nathan writes idiomatically, but that doesn’t mean his music is easy to play. “Multitude, Solitude” relies heavily on glissandos, moving the finger up or down the string between pitches, without lifting the bow. Momenta accomplished these flawlessly, individually and in various ensemble combinations, with consummate ease and awesome purity of intonation.

The end of the program was the last great work of the Czech composer Leos Janacek, his String Quartet No. 2 (“Intimate Letters”), composed in 1928. The subtitle refers to Janacek’s late-life passion for a married woman 38 years younger, the stimulus for an exchange of about 700 letters between them.

Momenta’s performances of Glass and Nathan were riveting, but the Janacek unleashed a veritable firestorm of intensity. The music quickly shifts between tenderness, longing, frustration and thwarted desire, undergirded by the earthiness of a Czech folk song. Momenta inhabited every note in an impassioned reading that combined brilliant virtuosity with the utmost sympathy and unity of intent. The immediate standing ovation suggested that I wasn’t the only listener who felt fortunate to be there.

Rucker is a freelance writer.