Comparative analysis of mass-spectral and thermochemical properties of XeF2, XeF4, and XeOF4

Mass spectra of individual species - XeF2, XeF4, XeF4 - and XeOF4 are measu red in the energy range from 10 to 30 eV by the method, in which the specie s are ionized by low-voltage electrons with the energy distribution width o f 0.1 eV. Using regularized deconvolution to remove energy:scatter of elect rons, we calculated the ionization energies (IE) and the energies of appear ance of ionic fragments (AE): IE(XeF2)=12.41+/- 0.05; IE(XeF4)=12.69+/-0.05 ; IE(XeOF4)=12.88+/-0.05; AE(XeF+)= 10.41+/-0.05 eV (from XeF2); AE(XeF+)=1 3.04+/-0.12, AE(XeF2+)= 15.095+/-0.12, AE(XeF3+)=12.91+/-0.07 eV (from XeF4 ); AE(XeF+)= 13.50+/-0.05, 15.7+/-0.2, AE(XeF2+))=15.715+/-0.07, AE(XeF3+)= 13.36+/-0.08, AE(XeF4+)=(13.23+/-0.07) eV (from XeOF4). The experimental da ta on IE and AE are used to calculate ionization energy IE(XeF)= (11.24+/-0 .05) eV and energies of bond rupture D-0(F-XeF3)=2.655+/-0.09, D-0(O-XeF4)= 0.529+/-0.046, D-0(F-Xe+)=0.99+/-0.05, D-0(F-XeF+)= 1.415+/-0.046, D-0(F-Xe F2+)=2.183+/-0.065, D-0(F-XeF3+)=0.19+/-0.054, D-0(O-XeF4+)=(0.35+/-0.086) eV. Enthalpies of XeOF4 sublimation and evaporation were assessed at Delta( s)H(0)=56.3+/-0.67 and Delta(upsilon)H(0)=38.67+/-0.9 kJ/mol from the tempe rature dependence of the saturated vapour pressure.