Sulphur ionization energy

For vanadium and chromium the first ionization energies are much lower than the first ionization energies of phosphorus and sulphur, respectively. This explains the high heats of formation of VC13 and CrCl3. In uranium, the tetravalent state is more stable than that in tungsten because uranium as an actinide has a different electron configuration. 

An evoked possibility of n-type doping of diamond with sulphur [219] has aroused an interest for the electronic properties of this element in diamond. It is now well established that, as expected from the properties of chalcogens in silicon and germanium, S behaves in diamond as a deep donor, with an ionization energy of 1 eV for S°, predicted from the ab initio DFT calculations [177]. However, the existence of S-related complexes with native defects or impurities like B is a possibility which could explain some appealing experimental results ([37], and references therein). 

Table 2. Vertical ionization energies / (in eV) of gaseous carbon (IV) and sulphur (VI) fluoride. The symmetry types of the M.O. are given with file numbers including the inner shells (in spite of the degenerate energies) and the major components in the LCAO description.

A paramagnetic ion attributed to S20 has been observed by e.p.r. spectra when H2S and SO2 are allowed to react on MgO at 25 °C. The proposed mechanism for the formation of S20 involves the reaction of elemental sulphur, as S2, with oxide ions of the MgO surface. The photoelectron spectra of H2C=S=0 ° and HN=S=0 have been recorded and the ionization energies of X=S=0 derivatives compared. ... 

The rate of the SN2 reaction (27 + 28 — 29) correlated well with the ionization potential of the lone pairs on the sulphur atom. The ionization potential was measured by photoelectron spectroscopy and is a direct measure of the energy of the HOMO. 

The explanation of this effect can be conceived as follows. Phenol has a fairly high dipole moment and has no low-energy acceptor orbitals, whereas iodine has no dipole moment hence interactions with iodine may be expected to have more covalent character than the analogous reactions with phenol. Accordingly, iodine will react more readily with the better polarizable reaction partners possessing lower ionization potentials. Similar considerations may be employed to interpret, for example, the sequence of basic strengths of primary, secondary and tertiary amines [Dr 63], and the sequence of acid strengths of iodine monochloride, elemental bromine, elemental iodine, phenol and sulphur dioxide [Dr 62]. 

The question of symmetry in 6a-thiathiophthens, in relation to the interpretation of various physical studies previously reported and to theoretical studies, is reviewed in a paper dealing with CNDO calculations of ionization and excitation energies, for the parent compound and its 2,S-dimethyl derivative. 6a-Thiathiophthen is included in a further theoretical study which covers a range of heterocyclic sulphur compounds. 

Compared to the PPP procedure with fixed core parameters, the refined methods do not offer much improvement in the calculation of transition energies or molecular ionization potentials. A similar conclusion was drawn following a comparison of results from different approximations. Zahradnik et al. have shown that the fixed parameter derived in reference 17 also permits discussion of the spectral data of sulphur-containing radicals by open-shell SCF calculation in the Longuet-Higgjns-Pople treatment. 

---