High resolution HeI and HeII photoelectron spectra of the thallium halides: valence bands and Tl 5d ligand field splittings

1983 ◽  
Vol 61 (12) ◽  
pp. 2669-2678 ◽  
Author(s):  
G. M. Bancroft ◽  
D. J. Bristow
Keyword(s):  
High Resolution ◽  
Valence Band ◽  
Photoelectron Spectra ◽  
Ligand Field ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
State Potential ◽  
Valence Bands ◽  
Good Agreement ◽  
Thallium Halides

We report high resolution photoelectron spectra of both the valence bands and Tl 5d levels of the thallium halides (TlX; X = Cl, Br, I) in the gas phase. A transition state Xα-SW calculation on TlCl agrees with previous valence band assignments, although our calculated orbital characters are quite different from those reported previously. The calculated spin–orbit splitting of the 22II state in TlI is in good agreement with the observed value of 0.83 eV. Line width variations are rationalized considering the increase in covalency from TlCl to TlI, and variations in the slope of the excited state potential curve.Ligand field splitting of the Tl 5d level has been resolved in all three compounds. The observed values of the non-cubic part of the crystal field (C20) are: −0.0210 eV (TlCl), −0.0233 eV (TlBr), and −0.0258 eV (TlI). The above trend is due to the increasing covalency from TlCl to TlI, with a concomitant increase in the Tl 6p orbital population. Calculated C20 values are in good agreement with those observed. The configuration interaction structure in the Tl 5d region is explained qualitatively using Xα-SW calculations of two-hole valence band energies in TlCl.

Spin -Orbit Coupling in the O-2 Anion

1995 ◽  
Vol 50 (11) ◽  
pp. 1041-1044 ◽  
Author(s):  
J. Schiedt ◽  
R. Weinkauf
Keyword(s):  
High Resolution ◽  
Electron Energy ◽  
Ground State ◽  
Photoelectron Spectroscopy ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Energy Analyzer ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Good Agreement

Abstract We could resolve the spin-orbit splitting of 160 ± 4 cm-1 in the 2II ground state of O2- anions by high resolution photodetachment photoelectron spectroscopy. The observed splitting is in good agreement with the theoretically derived value. Our directly measured electron affinity of O 2 is 450 ± 2 meV and deviates within experiment errors from previous values. kHz repetition rate was applied to avoid space charge and improve electron energy resolution in a time-of-flight electron energy analyzer.

The calculation of spin-orbit splitting and g tensors for small molecules and radicals

1973 ◽  
Vol 332 (1590) ◽  
pp. 365-384 ◽  
Keyword(s):  
Order Effects ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
First Order ◽  
Spin Orbit Splitting ◽  
Approximate Form ◽  
Firm Basis ◽  
Semi Empirical ◽  
Good Agreement

The spin-orbit coupling terms in the molecular electronic Hamiltonian have important, spectroscopically observable, effects. In states possessing an orbital degeneracy (e.g. II states of diatomic molecules) they produce a first-order splitting of the various multiplet levels; and in states which are degenerate in spin only the y give second-order effects embodied in a n effective g tensor. Owing to the complexity of the spin-orbit operators, such effects are usually discussed using simple approximate form s and semi-empirical wave-functions. In this paper, the complete operators are employed in ab initio calculations of (i) the spin-orb it splitting of the 2 II ground states of NO and CH, and (ii) the g tensors of CN and NO 2 . The results are in good agreement with experiment. Detailed analysis of the calculations indicates a firm basis for semi-empirical procedures which could easily be applied to larger molecules. The evaluation of new integrals, involving the spin-orbit operators, is discussed in an appendix.

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