Photoionization Efficiencies and Cross Sections in NH3

Excited States of the Molecular Ions of Hydrogen Fluoride, Hydrogen Iodide, Water, Hydrogen Sulphide, and Ammonia

“…This value of 10.4 v. for the first ionization potential of ammonia is confirmed by the photoionization work of Watanabe (24), though Walker and \Veissler (23) report that their photoionization studies showed that ionization set in a t 10.07 v.…”

“…This (le) orbital of ammonia is the main bonding orbital and it spans the three N-H bonds. It is interesting to note that Walker and Weissler (23) found evidence for a second ionization process setting in a little above 15 ev. They were, of course, not able to identify the cause of this, but our results a t least show that a t this energy there lies the first excited state of the NHS+ ion and so CVallter and Weissler's observation is a t least partly due to the formation of this excited state of the NH3+ ion.…”

Critical review of ultraviolet photoabsorption cross sections for molecules of astrophysical and aeronomic interest

“…and 1000 A; solid line, Metzger and Cook [1964a]; dashed line, Watanabe and Sood [1965]; +, Sun and Weissler [1955] ; X, Walker and Weissler [1955a], results were obtained with the helium continuum light source at instrumental bandwidths of 0.5 and 0.3 A, respectively. The results shown in Figure 46 are most disturbing, as the groups differ both in magnitude and shape as to the resultant absorption cross section curve.…”

“…The wavelength region between 580 A and 1340 A has been studied by Walker and Weissler [1955c], Watanabe [1954], Watanabe et al [1967], and…”

Ionization potentials of ammonia

“…of about 17 eV was suggested by Sun and Weissler (11), who found a sharp change in optical absorption at this energy. Later Walker and Weissler (7) observed an increase in NHB total photoionization efficiency a t approximately 15 eV, and they concluded that since the dissociation,…”