355nm激光作用下二甲胺的多光子电离质谱研究

利用多光子电离技术结合飞行时间质谱仪,在355nm激光作用下对二甲胺分子进行了研究,我们认为其主要经历了2＋1的REMPI过程,二甲胺母体离子α断裂产生CH3N＋H=CH2,CH3N＋H=CH2进一步解离产生C2H4N＋,用从头算方法确定了m/e=42的离子是（CH3N≡CH）＋,对m/e=28的离子的可能来源进行了推测：一是（CH3N≡CH）＋离子进一步发生重排,失去CH2游离基;二是CH2=N＋H21,2脱氢。

Study on multiphoton ionization mass spectrum of dimethylamine at 355nm laser radiation

The dimethylamine was studied by using multiphoton ionization technique and time-of-flight mass spectrometer under the radiation of the 355nm laser.we draw the conclusion that it mainly undergoes the 2＋1 REMPI process.The dimethylamine parent ion has gone through the α cleavage to produce CH3N＋H=CH2 fragment which later dissociates to C2H4N＋ fragment.The paper also obtains the result that the m/z 42 fragment is（CH3N≡CH）＋by the ab initio calculations,and,meanwhile,make speculation of the possible sources of m/z 28 fragment.One case is that the（CH3N≡CH）＋ undergoes the further rearrangement that causes the loss of CH2 radical.The other case is that the 1,2-hydrogen elimination from CH2=N＋H2.