Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

London dispersion dominating diamantane packing in helium nanodroplets.

ABSTRACT: Diamantane clusters formed inside superfluid helium nanodroplets were analyzed by time-of-flight mass spectrometry. Distinct cluster sizes were identified as "magic numbers" and the corresponding feasible structures for clusters consisting of up to 19 diamantane molecules were derived from meta-dynamics simulations and subsequent DFT computations. The obtained interaction energies were attributed to London dispersion attraction. Our findings demonstrate that diamantane units readily form assemblies even at low pressures and near-zero Kelvin temperatures, confirming the importance of the intermolecular dispersion effect for condensation of matter.

SUBMITTER: Alic J

PROVIDER: S-EPMC8494270 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

London dispersion dominating diamantane packing in helium nanodroplets.

Alić Jasna J Messner Roman R Lackner Florian F Ernst Wolfgang E WE Šekutor Marina M

Physical chemistry chemical physics : PCCP 20211006 38

Diamantane clusters formed inside superfluid helium nanodroplets were analyzed by time-of-flight mass spectrometry. Distinct cluster sizes were identified as "magic numbers" and the corresponding feasible structures for clusters consisting of up to 19 diamantane molecules were derived from meta-dynamics simulations and subsequent DFT computations. The obtained interaction energies were attributed to London dispersion attraction. Our findings demonstrate that diamantane units readily form assembl ...[more]

PMID: 34554159

Similar Datasets

Diamondoid ether clusters in helium nanodroplets.

Project description:Diamondoid ethers were introduced into superfluid helium nanodroplets and the resulting clusters were analyzed by time-of-flight mass spectrometry. Clusters of higher abundances (magic number clusters) were identified and the corresponding potential cluster geometries were obtained from GFN2-xTB and DFT computations. We found that the studied diamondoid ethers readily self-assemble in helium nanodroplets and that London dispersion attraction between hydrocarbon subunits acts as a driving force for cluster formation. On the other hand, hydrogen bonding between ether oxygens and trace water molecules fosters the eventual breakdown of the initial supramolecular aggregate.

| S-EPMC10155488 | biostudies-literature

Spectroscopy of corannulene cations in helium nanodroplets.

Project description:Helium tagging in action spectroscopy is an efficient method for measuring the absorption spectra of complex molecular ions with minimal perturbations to the gas phase spectra. We have used superfluid helium nanodroplets doped with corannulene to prepare cations of these molecules complexed with different numbers of He atoms. In total we identify 13 different absorption bands from corannulene cations between 5500 Å and 6000 Å. The He atoms cause a small, chemically induced redshift of the band positions of the corannulene ion. By studying this effect as a function of the number of solvating atoms we are able to identify the formation of solvation structures that are not visible in the mass spectrum. The solvation features detected using action spectroscopy agree very well with the results of atomistic modeling based on path-integral molecular dynamics simulations. By additionally doping our He droplets with D2, we produce protonated corannulene ions. The absorption spectrum of these ions differs significantly from the case of the radical cations as the numerous narrow bands are replaced by a broad absorption feature that spans nearly 2000 Å in width.

| S-EPMC6677026 | biostudies-literature

Size and Velocity Distribution of Negatively Charged Helium Nanodroplets.

Project description:Precharged helium nanodroplets can be used in doping experiments with the advantage that they are amenable to size selection with electrostatic fields, therefore adding a useful tuning parameter for dopant growth. For all these applications, the knowledge of the size distribution of charged droplets is an essential parameter, which we have so far assumed would be equivalent to that of their neutral precursors. Here, this assumption is experimentally investigated for negatively charged clusters for temperatures between 4 and 9 K at a stagnation pressure of 2 MPa. We observe a dependency of the velocity of the droplets on mass per charge, especially at the lowest temperatures of the investigated range, and values 20% lower than those known from the literature. Below 6 K, a large deviation from the literature is also found for the average droplet sizes. This information has to be taken into consideration in future experiments where large, charged droplets are sought to produce large dopant clusters. Possible origins for this deviation are discussed in the text.

| S-EPMC9282675 | biostudies-literature

Building Carbon Bridges on and between Fullerenes in Helium Nanodroplets.

Project description:We report the observation of sequential encounters of fullerenes with C atoms in an extremely cold environment. Experiments were performed with helium droplets at 0.37 K doped with C60 molecules and C atoms derived from a novel, pure source of C atoms. Very high-resolution mass spectra revealed the formation of carbenes of the type C60(C:)n with n up to 6. Bridge-type bonding of the C adatoms to form the known dumbbell C60═C═C60 also was observed. Density functional theory calculations were performed that elucidated the carbene character of the C60(C:)n species and their structures. Mass spectra taken in the presence of water impurities and in separate experiments with added H2 also revealed the formation of the adducts C60C(n)(H2O)n and C60C(n)(H2)n probably by H-OH and H-H bond insertion, respectively, and nonreactivity for the dumbell. So C adatoms that form carbenes C60(C:)n can endow pristine C60 with a higher chemical reactivity.

| S-EPMC4845062 | biostudies-literature

Long-lasting field-free alignment of large molecules inside helium nanodroplets.

Project description:Molecules with their axes sharply confined in space, available through laser-induced alignment methods, are essential for many current experiments, including ultrafast molecular imaging. For these applications the aligning laser field should ideally be turned-off, to avoid undesired perturbations, and the strong alignment should last long enough that reactions and dynamics can be mapped out. Presently, this is only possible for small, linear molecules and for times less than 1 picosecond. Here, we demonstrate strong, field-free alignment of large molecules inside helium nanodroplets, lasting >10 picoseconds. One-dimensional or three-dimensional alignment is created by a slowly switched-on laser pulse, made field-free through rapid pulse truncation, and retained thanks to the impeding effect of the helium environment on molecular rotation. The opportunities field-free aligned molecules open are illustrated by measuring the alignment-dependent strong-field ionization yield of dibromothiophene oligomers. Our technique will enable molecular frame experiments, including ultrafast excited state dynamics, on a variety of large molecules and complexes.

| S-EPMC6329814 | biostudies-literature

London Dispersion in Alkane Solvents.

Project description:The importance of London dispersion interactions in solution is an ongoing debate. Although the significance of dispersion for structure and stability is widely accepted, the degree of its attenuation in solution is still not properly understood. Quantitative evaluations are derived mostly from computations. Experimental data provide guidelines to include London dispersion in solution phase design. Herein, dispersive interactions were examined with an azobenzene probe. Alkyl substituents in meta positions of the azobenzene core were systematically varied and the effect on the half-lives for the thermally induced Z to E isomerization in several alkane solvents was determined. The results show that intramolecular dispersion is only marginally influenced. In solvents with low surface tension, reduced destabilizing solvent-solvent interactions increase the half-life up to 20 %. Specific individual interactions between alkyl chains on the azobenzene and those of the solvent lead to additional fluctuations of the half-lives. These presumably result from structural changes of the conformer ensemble.

| S-EPMC7821140 | biostudies-literature

Shell-Isolated Au Nanoparticles Functionalized with Rhodamine B Fluorophores in Helium Nanodroplets.

Project description:Nanoparticles consisting of three different materials in a layered core@shell@shell structure are synthesized in cold helium droplets by sequential doping. Upon the formation of Au core particles, a first shell layer is formed by adding either Ar, isopropyl alcohol, or hexane. Subsequently, the droplets are doped with rhodamine B (RB) molecules; fluorescence spectra recorded upon laser excitation at 532 nm provide insight into the structure of the formed complexes. For the two-component Au@RB system, the RB fluorescence is quenched in the presence of the Au core. If an intermediate isolating shell layer is introduced (Au@shell@RB), the fluorescence increases again. The results demonstrate that shell-isolated nanoparticles can be formed inside He nanodroplets and functionalized in situ with additional molecules. As the structure of the particles depends on the pickup sequence, the approach can be exploited for the synthesis and investigation of a large variety of different combinations of plasmonic metals, intermediate layers, and molecules.

| S-EPMC7812593 | biostudies-literature

Rydberg states of alkali atoms on superfluid helium nanodroplets: inside or outside?

Project description:Electronic excitations of an electron bound to an alkali metal ion inside a droplet of superfluid 4He are computed via a combination of helium density functional theory and the numerical integration of the Schrödinger equation for a single electron in a modified, He density dependent atomic pseudopotential. The application of a spectral method to the radial part of the valence electron wavefunction allows the computation of highly excited Rydberg states. For low principal quantum numbers, the energy required to push the electron outward is larger than the solvation energy of the ion. However, for higher principal quantum numbers the situation is reversed, which suggests the stability of a system where the ion sits inside the droplet while the valence electron orbits the nanodroplet.

| S-EPMC5708348 | biostudies-literature

SF<sub>6</sub><sup>+</sup>: Stabilizing Transient Ions in Helium Nanodroplets.

Project description:There are myriad ions that are deemed too short-lived to be experimentally accessible. One of them is SF6+. It has never been observed, although not for lack of trying. We demonstrate that long-lived SF6+ can be formed by doping charged helium nanodroplets (HNDs) with sulfur hexafluoride; excess helium is then gently stripped from the doped HNDs by collisions with helium gas. The ion is identified by high-resolution mass spectrometry (resolution m/Δm = 15000), the close agreement between the expected and observed yield of ions that contain minor sulfur isotopes, and collision-induced dissociation in which mass-selected HenSF6+ ions collide with helium gas. Under optimized conditions, the yield of SF6+ exceeds that of SF5+. The procedure is versatile and suitable for stabilizing many other transient molecular ions.

| S-EPMC8154854 | biostudies-literature

Spectroscopy of cold LiCa molecules formed on helium nanodroplets.

Project description:We report on the formation of mixed alkali-alkaline earth molecules (LiCa) on helium nanodroplets and present a comprehensive experimental and theoretical study of the ground and excited states of LiCa. Resonance enhanced multiphoton ionization time-of-flight (REMPI-TOF) spectroscopy and laser induced fluorescence (LIF) spectroscopy were used for the experimental investigation of LiCa from 15000 to 25500 cm(-1). The 4(2)Σ(+) and 3(2)Π states show a vibrational structure accompanied by distinct phonon wings, which allows us to determine molecular parameters as well as to study the interaction of the molecule with the helium droplet. Higher excited states (4(2)Π, 5(2)Σ(+), 5(2)Π, and 6(2)Σ(+)) are not vibrationally resolved and vibronic transitions start to overlap. The experimental spectrum is well reproduced by high-level ab initio calculations. By using a multireference configuration interaction (MRCI) approach, we calculated the 19 lowest lying potential energy curves (PECs) of the LiCa molecule. On the basis of these calculations, we could identify previously unobserved transitions. Our results demonstrate that the helium droplet isolation approach is a powerful method for the characterization of tailor-made alkali-alkaline earth molecules. In this way, important contributions can be made to the search for optimal pathways toward the creation of ultracold alkali-alkaline earth ground state molecules from the corresponding atomic species. Furthermore, a test for PECs calculated by ab initio methods is provided.

| S-EPMC3871282 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data