Conclusion The present investigation demonstrates that advanced photoelectron spectral techniques (VTPES, ADPES, and GSPES) are of considerable help in solving the rather complicated problem of rotational isomerism in tetramethyldiphosphine. In this way, it is established that the prevailing trans conformer (at room temperature) is more stable than the gauche isomer by 0.5 kcal/mol. Accordingly. at 170" C there is 50% of the trans form as ...
