Photoelectron spectra of methyl mercaptan, dimethyl sulfide, thiophenol, and .alpha.-toluenethiol. Bonding between sulfur and carbon

Articles you may be interested inCommunication: Vacuum ultraviolet laser photodissociation studies of small molecules by the vacuum ultraviolet laser photoionization time-sliced velocity-mapped ion imaging methodThe kinetic energy releases of the photodissociation processes, CH 3 SH + hv (193 nm) -.CH3 + SH, CH 3 S + H, and CH 2 S + H 2 • have been measured using the time-of-flight mass spectrometric method. These measurements allow the direct determination of the dissociation energies for the CH 3 -SH and CH3S-H bonds at 0 K as 72.4 ± 1.5 and 90 ± 2 kcal/mol, respectively. The further dissociation ofSH according to the process SH + hv (193 nm) -.S + H has also been observed. The appearance energy (AE) ofS produced in the latter process is consistent with the formation of S (3 P) + H. The photoelectron-photoion coincidence (PEPICO) spectra for CH 3 SH + , CH 3 S + (or CH 2 SH + ), and CH 2 S + from CH 3 SH have been measured in the wavelength range of 925-1460 A. The PEPICO measurements make possible the construction of the breakdown diagram for the unimolecular decomposition ofintemal-energy-selected CH 3 SH + in the range of 0-83 kcal/mol. The AE measured for CH 2 S + is consistent with the conclusion that the activation energy is negligible for 1,2-H2 elimination from CH 3 SH +. 946J. Chem. Phys. 95 (2), 15

Section: Tof Spectrum For Ch 2 Smentioning

confidence: 95%

“…(2) (3) is also proposed as a primary dissociation step in 185 nm photolysis. s The previous investigations are mostly kinetic in nature and have been made by monitoring the disappearance of the mercaptan and the appearance of stable products.…”

Section: Introductionmentioning

confidence: 99%

Vacuum ultraviolet photodissociation and photoionization studies of CH3SH and SH

Nourbakhsh

Norwood

Yin

et al. 1991

“…48 Our quantum chemical calculations of the molecular orbitals confirm that the thiol state, despite its broadness, is indeed due to only a single electronic level. 46 Therefore the Raman spectrum of the adamantane-1-thiol cation has been computed in its optimized geometry. 2 by five Gaussian peaks.…”

Section: B Occupied Statesmentioning

confidence: 99%

The influence of a single thiol group on the electronic and optical properties of the smallest diamondoid adamantane

Landt

Staiger

Wolter

et al. 2010

At the nanoscale, the surface becomes pivotal for the properties of semiconductors due to an increased surface-to-bulk ratio. Surface functionalization is a means to include semiconductor nanocrystals into devices. In this comprehensive experimental study we determine in detail the effect of a single thiol functional group on the electronic and optical properties of the hydrogen-passivated nanodiamond adamantane. We find that the optical properties of the diamondoid are strongly affected due to a drastic change in the occupied states. Compared to adamantane, the optical gap in adamantane-1-thiol is lowered by approximately 0.6 eV and UV luminescence is quenched. The lowest unoccupied states remain delocalized at the cluster surface leaving the diamondoid's negative electron affinity intact.

“…It has been argued before that the sulfur lone pair in thiophenol exhibits a considerable amount of interaction with the benzene ring. 73 This was based on the relative mag- nitude of the ionization potentials. Our ab initio calculation reveals that the both singly occupied molecular orbitals ͑SOMOs͒ for the X and Ã states of phenylthiyl are largely localized on the sulfur atom with little interaction with the adjacent benzene orbitals, as shown in Fig.…”

Section: B Molecule-frame Orbital Alignment Of the Phenylthiyl Radicmentioning

confidence: 99%

Experimental and theoretical study of the photodissociation reaction of thiophenol at 243nm: Intramolecular orbital alignment of the phenylthiyl radical

Lim

Lee

et al. 2007

The photoinduced hydrogen (or deuterium) detachment reaction of thiophenol (C(6)H(5)SH) or thiophenol-d(1) (C(6)H(5)SD) pumped at 243 nm has been investigated using the H (D) ion velocity map imaging technique. Photodissociation products, corresponding to the two distinct and anisotropic rings observed in the H (or D) ion images, are identified as the two lowest electronic states of phenylthiyl radical (C(6)H(5)S). Ab initio calculations show that the singly occupied molecular orbital of the phenylthiyl radical is localized on the sulfur atom and it is oriented either perpendicular or parallel to the molecular plane for the ground (B(1)) and the first excited state (B(2)) species, respectively. The experimental energy separation between these two states is 2600+/-200 cm(-1) in excellent agreement with the authors' theoretical prediction of 2674 cm(-1) at the CASPT2 level. The experimental anisotropy parameter (beta) of -1.0+/-0.05 at the large translational energy of D from the C(6)H(5)SD dissociation indicates that the transition dipole moment associated with this optical transition at 243 nm is perpendicular to the dissociating S-D bond, which in turn suggests an ultrafast D+C(6)H(5)S(B(1)) dissociation channel on a repulsive potential energy surface. The reduced anisotropy parameter of -0.76+/-0.04 observed at the smaller translational energy of D suggests that the D+C(6)H(5)S(B(2)) channel may proceed on adiabatic reaction paths resulting from the coupling of the initially excited state to other low-lying electronic states encountered along the reaction coordinate. Detailed high level ab initio calculations adopting multireference wave functions reveal that the C(6)H(5)S(B(1)) channel may be directly accessed via a (1)(n(pi),sigma(*)) photoexcitation at 243 nm while the key feature of the photodissociation dynamics of the C(6)H(5)S(B(2)) channel is the involvement of the (3)(n(pi),pi(*))-->(3)(n(sigma),sigma(*)) profile as well as the spin-orbit induced avoided crossing between the ground and the (3)(n(pi),sigma(*)) state. The S-D bond dissociation energy of thiophenol-d(1) is accurately estimated to be D(0)=79.6+/-0.3 kcalmol. The S-H bond dissociation energy is also estimated to give D(0)=76.8+/-0.3 kcalmol, which is smaller than previously reported ones by at least 2 kcalmol. The C-H bond of the benzene moiety is found to give rise to the H fragment. Ring opening reactions induced by the pi-pi(*)n(pi)-pi(*) transitions followed by internal conversion may be responsible for the isotropic broad translational energy distribution of fragments.