Electron Momentum Spectroscopy Study of Lone Pair Orbitals of Thiols and Dimethyl Sulfide

Abstract

Experimental momentum profiles of the lone pair orbitals of several thiols and dimethyl sulfide have been measured and compared with theoretical momentum profiles. All the observed profiles exhibit p-type character, confirming that the orbitals have been characterized as sulfur nonbonding orbitals. However, small shifts in the profiles are found, depending on substituents. The results are discussed in relation to the geometries of the molecules.

Conformationally Specific Vacuum Ultraviolet Mass-Analyzed Threshold Ionization Spectroscopy of Alkanethiols: Structure and Ionization of Conformational Isomers of Ethanethiol, Isopropanethiol, 1-Propanethiol, tert-Butanethiol, and 1-Butanethiol

“…As indirectly known from the electron momentum spectroscopic study, the HOMO of the neutral ground-state of ethanethiol is mainly localized on sulfur, while it has a nodal plane bisecting the C−S bond (Figure ). Furthermore, it is found that, from the CASSCF(3,4) calculation with a 6-31G** basis set, the singly occupied molecular orbital (SOMO) of the ethanethiol cation is not only localized on sulfur, but it is also fully occupied, meaning that the multireference nature of the orbital may not be significant in this case.…”

The impact energy dependence of momentum profiles of glyoxal and biacetyl and comparison with theory at their high-energy limits

“…Very recently, we have developed an energy-and angle-dispersive EMS spectrometer [11]. It has taken a significant advantage of multichannel detection, realizing experiments at much higher precision than achieved with our previous apparatus [12].…”

Electron Momentum Spectroscopy Study on the Valence Electronic Structure of Dimethyl Sulfide Considering Vibrational Effects

“…The valence orbitals of (CH 3 ) 2 S were also investigated by electron momentum spectroscopy (EMS). , EMS is a unique technique for exploring electronic structures of atoms and molecules. It is based on the fast electron impact binary (e, 2e) reaction near the Bethe ridge condition. − Within a series of approximations including binary encounter, weak coupling, plane wave impulse, as well as target Hartree–Fock (HF) or target Kohn–Sham (KS) approximations, , the measured (e, 2e) triple differential cross section (TDCS) is proportional to the spherically averaged modulus square of the electron wave function of the ionized orbital in the momentum space or the electron momentum profile (EMP).…”

“…It is based on the fast electron impact binary (e, 2e) reaction near the Bethe ridge condition. − Within a series of approximations including binary encounter, weak coupling, plane wave impulse, as well as target Hartree–Fock (HF) or target Kohn–Sham (KS) approximations, , the measured (e, 2e) triple differential cross section (TDCS) is proportional to the spherically averaged modulus square of the electron wave function of the ionized orbital in the momentum space or the electron momentum profile (EMP). Takahashi et al obtained the EMP of 3b 1 , the highest occupied molecular orbital (HOMO) of (CH 3 ) 2 S, with limited statistics. The shift of the EMP to higher momentum was observed due to the delocalization of the sulfur 3p lone pairs.…”

“…21−23 The valence orbitals of (CH 3 ) 2 S were also investigated by electron momentum spectroscopy (EMS). 24,25 EMS is a unique technique for exploring electronic structures of atoms and molecules. It is based on the fast electron impact binary (e, 2e) reaction near the Bethe ridge condition.…”