decompose

decompose
/ˌdi:kəmˈpəuz; ˌdikəm`poz/ v
1 [I, Tn] (cause sth to) become bad or rotten; decay （使某物）变坏, 腐烂
    a decomposing corpse 腐尸.
2 [Tn] separate (a substance, light, etc) into its parts 分解（某物质、 光线等）
    A prism decomposes light. 棱镜可以分解光线.

牛津英汉双解词典