Stefanov André, Stibor Alexander, Dominguez-Clarimon Alex, Arndt Markus
Institut für Experimentalphysik, Universität Wien, Boltzmanngasse 5, A-1090 Wien, Austria.
J Chem Phys. 2004 Oct 8;121(14):6935-40. doi: 10.1063/1.1792551.
We present an in-flight fluorescence detection scheme for molecular beams which is applied to determine the enthalpy of sublimation of dye molecules. We investigate tetraphenylporphyrin (TPP), porphine, and nile red, which are believed to be suitable candidates for molecular de Broglie wave interferometry. The measured values are H(sub)(TPP)=142+/-3 kJ/mol, H(sub)(porphine)=87+/-3 kJ/mol, and H(sub)(nile red)=66+/-2 kJ/mol. For TPP, sublimation enthalpies differ in the literature by more than a factor of 2. Our measurements confirm a value at the lower end of this scale. We discuss changes in the character of the molecular flow with the source temperature as a prime reason for discrepancies in the published data.
我们提出了一种用于分子束的飞行中荧光检测方案，该方案用于测定染料分子的升华焓。我们研究了四苯基卟啉（TPP）、卟吩和尼罗红，它们被认为是分子德布罗意波干涉测量的合适候选物。测量值为H（sub）（TPP）=142±3 kJ/mol，H（sub）（卟吩）=87±3 kJ/mol，H（sub）（尼罗红）=66±2 kJ/mol。对于TPP，文献中的升华焓相差超过2倍。我们的测量结果证实了该范围下限的值。我们讨论了分子流特性随源温度的变化，这是已发表数据存在差异的主要原因。
