Erratum: Investigating conformation dependence and nonadiabatic effects in the photodissociation of allyl chloride at 193 nm [J. Chem. Phys. 104, 5446 (1996)]
Correction for ‘Photodissociation dynamics of fulvenallene and the fulvenallenyl radical at 248 and 193 nm’ by Isaac A. Ramphal et al., Phys. Chem. Chem. Phys., 2017, DOI: 10.1039/c7cp05490d.
Ablation of thick (≈ 15 μm) films of C6H6, C6H5CH3 and C6H5CI at 248 nm and 193 nm
is studied by means of time-of-flight quadrupole mass spectrometry. The dependence of
the desorbate most probable translational energies on laser fluence is determined over the
≈20–200 mJ/cm2 range. In all cases, the corresponding diagrams are found to exhibit
“plateaus”, in accord with the report by Braun and Hess [J. Chem. Phys. 99 (1993) 8330].
However, no specific correlation with the thermodynamic properties of the compounds is
observed, thereby questioning the attribution of the “plateaus” to phase transformation
of the films under ablation conditions. A high sensitivity of the distributions and intensities
on the rate of deposition and the irradiation history of the films is observed,
indicating the importance of the matrix “structure” for the distribution of the absorbed
energy. On the other hand, the analysis of the total translational energies of the desorbates
suggests that during ablation, efficient energy transfer occurs in the film. This
possibility is further demonstrated by the observation of high translational energies and
sputtering yields for C6H12(nonabsorbing at 248 nm) condensed in thickness of ≈ I μm
on top of C6H5CH3 films. These observations can be qualitatively explained in terms of
the collisional sequence model. Alternatively, a photothermal model may be applicable
under the provision that energy distribution in the films is limited due to imperfections
introducing barriers (bottlenecks) to its ‘flow’.
We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from <i>Synechococcus elongatus</i>, <i>Thermococcus vulcanus</i>, and <i>Rhodobacter sphaeroides</i>, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.
The GMTKN55 benchmarking protocol introduced by [Goerigk et al., Phys. Chem. Chem. Phys., 2017, 19, 32184] allows comprehensive analysis and ranking of density functional approximations with diverse chemical behaviours. But this comprehensiveness comes at a cost: GMTKN55's 1500 benchmarking values require energies for around 2500 systems to be calculated, making it a costly exercise. This manuscript introduces three subsets of GMTKN55, consisting of 30, 100 and 150 systems, as `diet' substitutes for the full database. The subsets are chosen via a stochastic genetic approach, and consequently can reproduce key results of the full GMTKN55 database, including ranking of approximations.
Erratum: Doppler spectroscopy of chlorine atoms generated from photodissociation of hydrogen chloride and methyl chloride at 157 and 193 nm [J. Chem. Phys. 92, 1696 (1990)]