Themed collection Developments in Ultrafast Spectroscopy

Guest editors, Chantal Daniel, Luis Banares, Spiridoula Matsika and Jin Zhao, introduce this Physical Chemistry Chemical Physics themed issue.

The correlation between electronic densities and active molecular vibrations drives the spin–vibronic mechanism of ultrafast decays in coordination chemistry.

Long-term stability and suppressed power-conversion efficiency degradation achieved with inorganic charge transport layers.

Pump–repump–probe spectroscopy with a burst mode of photoexcitation was applied to the direct observation of the photoionization dynamics of perylene in the solution phase.

In this work, the hot carrier relaxation processes in CsPbBr₃ nanocrystals were studied through ab initio non-adiabatic molecular dynamics simulations.

DP-HPPI displays a reversible ESIPT reaction in DCM and breaking of intramolecular H-bonds in ACN.

We report a benchmark of excited state absorption of the four DNA bases using ab initio (EOM-CCSD, EOM-CC3) and TD-CAM-B3LYP methods, in the gas phase and in chloroform, a step towards the interpretation of time-resolved absorption spectra in solution.

The photoexcited carrier lifetime in semiconductors plays a crucial role in solar energy conversion processes.

Vibrationally resolved absorption spectra in α-phase and β-phase zinc phthalocyanine (ZnPc) aggregates.

The alignment perpendicular to the field of the molecular axis in dissociative excited states of single electron molecules, prevents quantum control by bond hardening. However, using circularly polarized fields, one can circumvent this problem.

Ultrafast photophysics in the single chain of a PM6 is studied. The time evolution of locally excited (LE) and charge-transfer (CT)/separated (CS) states depends on the chain length highlighting effects of chain foldings on generating carriers.

Chemiexcitation of 1,2-dioxetanes is initiated by the cleavage of the O–O bond, then the molecule enters a region where nonadiabatic transitions to excited states are feasible. Does the surface topography explain chemiexcitation yield differences?

A novel tandem design of sensitized BODIPY photolabile protecting groups is presented and characterized by combined spectroscopic and computational studies, paving the way for a new generation of functionalized photoactive compounds.

The effect of the incident UV pump wavelength on the subsequent excited state dynamics, electronic relaxation, and ultimate dissociation of formaldehyde is studied using first principles simulation and Coulomb explosion imaging (CEI) experiments.

A macroscopic model of exciton density decays in disordered molecular systems, including contributions from molecular aggregate quenchers, is proposed. The model can be applied to ultrafast decays of dyes and for global fitting of experimental data.

The excitation on the librational band of liquid water at 12.3 THz resonates with the rotationally-damped motion of water molecules.

The ground state unimolecular decay of Criegee intermediates may potentially be influenced by conical intersections.

Photoexcitation of 1- and 2-propanol initiates a variety of molecular dynamics such as fragmentation, hydrogen migration, and even possible methyl roaming (only in 2-propanol).

Ultrafast vibrational dynamics induced by XUV excitation was investigated in diamondoids using HHG light source.

Time resolved M_2,3-edge XANES spectroscopy of the Co₄O₄ cubane reveals ultrafast intersystem crossing into a quintet state within 38 fs.

Rydberg-like image potential states (IPSs) form special series surface states on metal and semiconducting surfaces.

Photo-oxa-dibenzocyclooctyne (Photo-ODIBO) undergoes photodecarbonylation under UV excitation to its bright S₂ state, forming a highly reactive alkyne, ODIBO.

Both hot electron injection and a near field enhancement effects on water splitting reaction at the nanoscale are investigated by the hybird FDTD/TDDFT approach.

We study the isomeric effects using time resolved photoelectron circular dichroism (TR-PECD).

Photolysis reaction channels of CH₃ONO₂ are obtained in the nonadiabatic dynamics simulations.

The photochemistry of metal–organic compounds in solution is determined by both intra- and inter-molecular relaxation processes after photoexcitation.

Coherent internal conversion between higher electronic excited states is observed directly by excitation of molecules to S_n (n ≥ 2) state and detection of fluorescence from S₁ state by wave-packet-resolved time-resolved fluorescence.

We explore how ultrafast spectroscopy can be utilised to predict the longer-term efficacy of avobenzone in sunscreen formulation models.

The photochemistry of a molybdenum complex bearing both carbonyl and nitrosyl ligands is investigated by ultrafast spectroscopy and quantum-chemical calculations with the goal to elucidate possibilities of photoinduced ligand release.

The spectral and temporal profiles of exciton delocalization length in chlorosomes are determined with two-dimensional electronic spectroscopy.

Effects of experimental parameters – including laser pulse duration, photon energy, aperture diameter, and cathode size – on single-electron temporal resolution are explored via particle-tracer simulations in ultrafast electron microscopy.

The ellipticity of a laser can control the dissociation pathways of ethane dications produced by strong fields.

A global-switching trajectory surface hopping method on TDDFT potential energy surfaces has been used to simulate complex conical intersection networks and to predict photoproduct quantum yield distributions for a real RPSB system.

Transient absorption spectroscopy reveals the excited state dynamics of meta- and para-methyl anthranilate in solution. Implicit solvent computational methods insufficiently model these systems's behaviour, implying the need for explicit solvent models.

This study provides the basis for the reliable and quantitative comparison of experimentally determined exciton dynamics in TMDCs from independent femtosecond time-resolved optical spectroscopy experiments on different samples and substrates.

A frequency filter enhances ionization–excitation versus excitation–ionization, suppressing channels that prevent the extraction of the dynamical information in an experiment.

We implement spin–orbit coupling (SOC) within the framework of the OMx/CIS method and then incorporate it into Tully's fewest switches surface hopping algorithm to enable excited-state nonadiabatic dynamics simulations.

Ultrafast vibrational wave packet dynamics of the tyrosyl radical anion provide insight into sub-picosecond structural rearrangements induced by ionizing radiation.

Femtosecond UV/MIR spectroscopy reveals the binding mode isomerization of an iron–carbon dioxide complex following the impulsive photolysis of iron oxalate precursor.

Theoretical studies demonstrate that the polymerization degree of molecules encapsulated in carbon nanotubes can be used to tune their interfacial and optoelectrical properties.