We have measured the negative ion photoelectron spectra of CH2Nminus;and CD2Nminus;and find the electron affinities: EA(CH2N)=0.511plusmn;0.008 eV and EA(CD2N)=0.498plusmn;0.011 eV. Franckndash;Condon simulations of these spectra are carried out and we estimate the CH2Nminus;and CH2N geometry differences; we fit our spectra with the following lsqb;constrainedrsqb; molecular structures. We combine our EA(CH2N) with the results of previous gas phase ion studies to extract a number of thermochemical parameters (kcal/mol):Do0(CH2Nndash;H)=85plusmn;5,Do0(Hndash;HCN)=23plusmn;6,Do0(H2Cndash;N)=144plusmn;6, and the isomerization enthalpy of H2CN+rarr;HCNH+is Dgr;Hisom(C2vrarr;Cinfin;v)=minus;51plusmn;7. Attempts to calculate the geometry and vibrational frequencies of the H2CN radical are disappointing. Unrestricted Hartreendash;Fock and secondhyphen;order Moslash;llerndash;Plessetabinitiocalculations in a 6hyphen;31++Gast;ast; basis produce badly spinhyphen;contaminated wave functions which do not reproduce the experimental findings.
展开▼
