Effect of Temperature on the Structure of Gaseous Molecules. Molecular Structure of PCl3at 300deg; and 505deg;K

摘要

The molecular structure of PCl3has been studied by electron diffraction from the vapor at nozzle temperatures of 300deg; and 505deg;K. Both the size of the molecule and the displacement of the atoms during molecular vibration are found to be significantly greater at the higher temperature: The Psngbnd;Cl and Clmiddot;middot;middot;Cl distances are longer by 0.3 and 0.4, respectively, and the rms amplitudes associated with these distances are greater by a striking 19 and 31. Both the increased size of the molecule and increased amplitudes are in very good agreement with prediction from simple theory. The results at 300deg; and 505deg;K, respectively, arerPhyphen;Cl=2.039plusmn;0.0014 A and 2.045plusmn;0.0016 A;rClmiddot;middot;middot;Cl=3.130plusmn;0.0026 A and 3.142plusmn;0.0038 A; Clsngbnd;Psngbnd;Cl=100.27plusmn;0.09deg; and 100.40plusmn;0.16deg;;lPhyphen;Cl=0.0501plusmn;0.0013 A and 0.0594plusmn;0.0017 A;lClmiddot;middot;middot;Cl=0.0834plusmn;0.0023 A and 0.1097plusmn;0.0035 A. The interatomic distances given areravalues obtained from the third cycle of leasthyphen;squares refinement of intensity curves and differ from the equilibrium valuesreby small amounts; thelijvalues differ similarly from thelevalues. The estimated standard errors include standard deviations derived from the leasthyphen;squares procedure, estimates of correlation among the data, uncertainty in the constants of the experiment, and uncertainty in the factors employed in the data reduction.