The Ag colloid of 18 A in radius was estimated from measurements of the half-width of the plasma resonance by using the Mie theory and Doyle method.

• 运用米(Mie)理论和德拜(Doyle)方法；根据测得的等离子共振峰的光宽度；估算出Ag胶态粒子的半径约为18(?) .