The ionization threshold ofN,N,Nrsquo;,Nrsquo;hyphen;tetramethylhyphen;phyphen;phenylenediamine in dense fluid ethane; effects of fluid density and temperature

摘要

The ionization thresholdIFofN,N,Nrsquo;,Nrsquo;hyphen;tetramethylhyphen;phyphen;phenylenediamine in ethane, has been measured in the density (rgr;) range 0.15ndash;13.30 M/land over the temperature (T) range 295ndash;413 K, using a multiphoton ionization conductivity technique. TheIFwas found to be a function of both rgr; andTin the ranges studied. At a fixedT(=373 K),IFwas found first to decrease with increasing rgr; and then to level off at densities of sim;10 M/l. For rgr;ge;11 M/landT=295 K, theIFwas found to increase with increasing density. At constant density (rgr;=5.90 M/lthinsp;)IFdecreased with increasingTbetween 323 and 413 K. These results are analyzed and discussed in relation to the effect of rgr; andTon the electron conduction band energyV0and the medium polarization energyP+. The changes in theIFwith rgr; are attributed to the dependence ofV0andP+on rgr;, while the dependence ofIFonTis attributed to the effects ofTonV0rather than onP+.