VUV photoionization of the CH2NC radical: adiabatic ionization energy and cationic vibrational mode wavenumber determinations

The photoelectron spectroscopy of CH2NC (isocyanomethyl) radical species is investigated for the first time between 9.3 and 11.2 eV in the vicinity of the first photoionizing transition X+1A1 ← X 2B1.

Detailed analysis of the vibronic structure of phenetole in its first excited state and ionic ground state

The vibronic structure of the first electronically excited state S1 and ionic ground state D0 of phenetole has been investigated by means of resonance enhanced multi photon ionization (REMPI) and mass analyzed threshold ionization (MATI) spectroscopy. The vibronic levels were assigned with the aid of quantum chemical calculations at the (TD)DFT level of theory and a multidimensional Franck-Condon approach. The S1 excitation energy of phenetole has been determined to be 36370 ± 4 cm−1 (4.5093 ± 0.0005 eV). The adiabatic ionization energy was determined to be 65665 ± 7 cm−1 (8.1415 ± 0.0008 eV). The vibronic structure has been analyzed whereby the in-plane bending vibration νbend shows high activity in the first excited state but is more pronounced in the ionic ground state. Moreover, a strong Duschinsky rotation effect can be observed for several D0←S1 transitions that causes violations of the Δv = 0 propensity rule.

Explicit solvent simulations of the aqueous oxidation potential and reorganization energy for neutral molecules: gas phase, linear solvent response, and non-linear response contributions

Explicit solvent simulations are used to partition the aqueous adiabatic ionization potential (AIEaq) into the gas phase adiabatic ionization energy (AIEgas), linear solvent response (ΔΔGLRAsolv), and non-linear solvent response (ΔΔΔGnon-LRsolv) contributions.

DFT INSIGHT INTO THE UV-VIS SPECTRA AND RADICAL SCAVENGING ACTIVITY OF AURANTIO-OBTUSIN

Aurantio-obtusin (2,6,8-trihydroxy-1,7-dimethoxy-3-methyl anthraquinone), an anthraquinone derivative isolated from the seeds of Cassia tora L., has been studied by DFT calculations at the B3LYP/6-311+g(2df,p)//B3LYP/6–31G(d,p) level in vacuum and in methanol polarized continuum model (PCM). Eight conformers have been located by conformational search and optimization. Our results indicate that the titled compound has planar structures, and five intramolecular hydrogen bonds are found in the lowest-energy structure, including three OH⋯O and two CH⋯O hydrogen bonds. The electronic spectra in methanol have been determined by the time-dependent density functional theory (TD-DFT) approach, showing that the first singlet exited state of the title compound arises from π → π* electron transition. The antioxidant activity of aurantio-obtusin is evaluated by means of calculating O−H bond dissociated enthalpy (BDE) and the adiabatic ionization energy (IE). The calculated BDE and IE values of aurantio-obtusin are 341.8 and 732.3 kJ mol-1, respectively, lower than the corresponding values of phenol (348.4 and 801.7 kJ mol-1) and purpurin (360.4 and 747.8 kJ mol-1), suggesting that aurantio-obtusin is a better antioxidant.