NaD雙線[(D1)=5895.92Å,由3P1/2躍遷至3S1/2;(D2)=5889.95Å,由3P3/2躍遷至3S1/2]的相對(duì)強(qiáng)度比I(D1)/I(D2)應(yīng)為()。