Role of Dark States and Stokes Shift Simulations for Tetraphenylpyrazine Compared to Other Donor-Acceptor Photosensitizers.

An excellent agreement for simulated and measured absorption and emission spectra is found for four donor-acceptor aromatic molecules (tetraphenylpyrazine, tetraphenylethene, distirylanthracene and hexaphenylsilole) whose derivatives serve as solid state photosensitizers. After comparing several hybrid TDDFT functionals, EOM-CCSD, and experiments, the best agreement was found with TD-B3LYP and double zeta basis sets (6-31G** and def2-SVP) for one molecule in gas phase. A full characterisation of twelve to twenty electronic excited states was performed in every system.

Methane dimer rovibrational states and Raman transition moments.

Benchmark-quality rovibrational data are reported for the methane dimer from variational nuclear motion computations using an intermolecular potential energy surface reported by [M. P. Metz , , 2019, , 13504-13525].

Photofragmentation of cyclobutanone at 200 nm: TDDFT vs CASSCF electron diffraction.

To simulate a 200 nm photoexcitation in cyclobutanone to the n-3s Rydberg state, classical trajectories were excited from a Wigner distribution to the singlet state manifold based on excitation energies and oscillator strengths. Twelve singlet and 12 triplet states are treated using TD-B3LYP-D3/6-31+G** for the electronic structure, and the nuclei are propagated with the Tully surface hopping method. Using time-dependent density functional theory, we are able to predict the bond cleavage that takes place on the S1 surface as well as the ultrafast deactivation from the Rydberg n-3s state to the nπ*.

Coronene: a model for ultrafast dynamics in graphene nanoflakes and PAHs.

Assuming a delta pulse excitation, quantum wavepackets are propagated on the excited state manifold in the energy range from 3.4-5.0 eV for coronene and 2.

Vibrational infrared and Raman spectra of HCOOH from variational computations.

All vibrational energies of the formic acid molecule in different forms (-, -, -) were converged up to 4500 cm beyond the zero-point vibrational energy with the GENIUSH-Smolyak variational approach and using an potential energy surface [D. P. Tew and W.

Exact quantum dynamics developments for floppy molecular systems and complexes.

Molecular rotation, vibration, internal rotation, isomerization, tunneling, intermolecular dynamics of weakly and strongly interacting systems, intra-to-inter-molecular energy transfer, hindered rotation and hindered translation over surfaces are important types of molecular motions. Their fundamentally correct and detailed description can be obtained by solving the nuclear Schrödinger equation on a potential energy surface. Many of the chemically interesting processes involve quantum nuclear motions which are 'delocalized' over multiple potential energy wells.

High-dimensional neural network potentials for accurate vibrational frequencies: the formic acid dimer benchmark.

In recent years, machine learning potentials (MLP) for atomistic simulations have attracted a lot of attention in chemistry and materials science. Many new approaches have been developed with the primary aim to transfer the accuracy of electronic structure calculations to large condensed systems containing thousands of atoms. In spite of these advances, the reliability of modern MLPs in reproducing the subtle details of the multi-dimensional potential-energy surface is still difficult to assess for such systems.

Performance of a black-box-type rovibrational method in comparison with a tailor-made approach: Case study for the methane-water dimer.

The present work intends to join and respond to the excellent and thoroughly documented rovibrational study of X. G. Wang and T.

Fingerprint region of the formic acid dimer: variational vibrational computations in curvilinear coordinates.

Curvilinear kinetic energy models are developed for variational nuclear motion computations including the inter- and the low-frequency intra-molecular degrees of freedom of the formic acid dimer. The coupling of the inter- and intra-molecular modes is studied by solving the vibrational Schrödinger equation for a series of vibrational models, from two up to ten active vibrational degrees of freedom by selecting various combinations of active modes and constrained coordinate values. Vibrational states, nodal assignment, and infrared vibrational intensity information is computed using the full-dimensional potential energy surface (PES) and electric dipole moment surface developed by Qu and Bowman [Phys.