Thermal and electrical properties of porphyrin derivatives and their relevance for molecule interferometry.

The authors present new measurements of thermal and electrical properties for two porphyrin derivatives. They determine their sublimation enthalpy from the temperature dependence of the effusive beam intensity. The authors study H2TPP and Fe(TPP)Cl in matter-wave interferometry. Both molecules have nearly equal de Broglie wavelengths but different internal characteristics: only Fe(TPP)Cl exhibits an electric dipole moment of about 2.7 D and the authors discuss its influence on the molecular interference pattern. The authors add an external electric force field to the interferometer and use it to measure the scalar polarizability. They compare their experimental values alpha(H2TPP)=105+/-4+/-6 A3 and alpha(Fe(TPP)Cl)=102+/-9+/-6 A3 to ab initio calculations and they discuss the influence of thermal excitations on the polarizability.