Thi Thuy Duong N, Tuan Cuong N. STUDY ON GEOMETRICAL STRUCTURES AND ABSORPTION SPECTRA OF M\(_4\)\(^{2+}\) CLUSTERS (M = Cu, Ag, Au) ENCAPSULATED IN SAPO-42 ZEOLITE \(\beta\)-CAGE USING DENSITY FUNCTIONAL THEORY. HNUEJS.NS. 2024;69(3):87-95. doi:10.18173/2354-1059.2024-0038