Probing the Molecular Environment Using Spin-Resolved Photoelectron Spectroscopy

Angle- and spin-resolved photoelectron spectroscopy with linearly and circularly polarized synchrotron radiation were used to study the electronic structure of model triatomic molecules, hydrogen sulfide, and carbonyl sulfide. The spin-polarization measurements of the molecular field split components of the S $2p$ photolines revealed a strong effect of the different molecular environments. The validity of simple atomic models to explain the results is discussed.

Figure 1

S $2p$ photoionization spectrum of OCS, measured with 205 eV circularly polarized light. Bottom: total intensity; the continuous curves are the result of a least-squares fitting procedure. Top: spin polarization; calculated from (●) the peak areas and (○) the individual data points.

Figure 2

Spin polarization of the S $2p$ photoelectrons in OCS as a function of (circularly polarized) photon energy. Experimental points are for the ground vibrational state of the ($*=A_0$) S $2p_{1/2}$ and ($●=B_0$, $○=C_0$) molecular field split S $2p_{3/2}$. Solid lines are calculations for Ar $2p$ photoionization.

Figure 3

Spin polarization of the S $2p$ photoelectrons in the ${\mathrm{H}}_2\mathrm{S}$ molecule as in Fig. 2. The spin polarization of the (□) sum of the S $2p_{3/2}$ lines is also reported.

Figure 4

Anisotropy parameters of the unresolved doublet $B_0+C_0$ [(○) ${\mathrm{H}}_2\mathrm{S}$, (●) OCS [20]] and difference in the anisotropy coefficients of the two lines [(▽) ${\mathrm{H}}_2\mathrm{S}$, (▲) OCS [20]]. Ar calculations are reported as solid lines.