Size‐selective infrared photodissociation spectra of (CH3OH)n clusters from n=2 to n=9 were measured near the absorption band of the C–O stretching mode of the monomer at 1033.5 cm−1 . The experiments were carried out in a molecular‐beam apparatus in which the clusters are generated in a supersonic expansion and afterwards size selected in a scattering experiment with helium atoms. The internally excited clusters are dissociated by the radiation of a cw CO2 laser in a new antiparallel arrangement of the scattered cluster beam and laser beam. The observed spectra vary from the dimer, for which a double‐peak structure appears, to the single‐peak spectra of the trimer, tetramer, and pentamer which are continuously shifted to higher frequencies. A special transition is seen from the pentamer to the hexamer, for which again a double‐peak structure is observed which continues to larger clusters. Applying an intermolecular model potential, a correlation between the observed spectra and the cluster configuration ...

/pdf/infrared-photodissociation-of-size-selected-methylamine-7t6wsymffw.pdf

Infrared photodissociation of size-selected methylamine clusters

Infrared photodissociation of size-selected small ammonia clusters

A method for predicting splittings and shifts of bands in infrared spectra of small clusters of polyatomic molecules is presented Based on an approach of early publications of Buckingham, the influence of the intermolecular forces on the vibrational energy levels of the constituent molecules is calculated using perturbation theory to second order In order to describe the interaction of identical molecules, this ansatz is extended to also cover degenerate systems In first order, a coupling of the vibrational modes of the interacting molecules occurs which leads to delocalized vibrations of all the molecules in the cluster The second order correction of the vibrational excitation frequencies are found to be dominated by the intramolecular couplings of the normal modes due to the cubic anharmonicity of the force field The procedures developed here are applied for the interpretation of vibrational photodissociation spectra of small methanol clusters in the region of the fundamental excitation frequency o

A perturbation approach to predict infrared spectra of small molecular clusters applied to methanol

The infrared photodissociation of size‐selected, small benzene clusters has been investigated in the region of the ν18 CH in‐plane bend using a pulsed CO2 laser. By scattering the cluster beam with a secondary Ne beam and observing off‐axis the effect of the laser irradiation with a rotatable mass spectrometer, cluster‐specific spectroscopy is performed. The dependence of IR absorption and subsequent dissociation of (C6H6)n clusters has been investigated as a function of laser frequency and laser fluence for n=2, 3, and 4. The absorption profiles are structureless and show only little variation with cluster size. If, instead of He, Ne is used as carrier gas, the absorption profiles are distinctively narrower. This effect is attributed to a lower internal temperature achieved with Ne. In contrast to the benzene dimer and tetramer, the fluence dependence for the trimer dissociation is stronger than linear suggesting that more than one photon is needed to dissociate this cluster. In a computational approach,...

CO2‐laser induced photodissociation studies of size‐selected small benzene clusters

Infrared Vibrational Predissociation Spectroscopy of Small Size‐Selected Clusters

Ethylene clusters (C2H4)n are generated in a supersonic expansion with He and size selected by scattering from a helium beam. The clusters are dissociated upon absorption of a photon from a pulsed CO2 laser by exciting the ν7 mode of the monomer. During the collision about 30 meV of internal energy is transferred to the cluster so that the laser photons interact with internally hot clusters. The frequency and fluence dependences of the photodissociation cross sections are measured for (C2H4)n with n=2,3,4,5, and 6. Nearly all spectra exhibit structure which is most pronounced for the dimer. The overall width (FWHM) decreases from 31.2 cm−1 for the dimer to 12.2 cm−1 for the hexamer, while the maximum position is nearly the same (951.6 cm−1). The structure of the dimer spectrum is attributed to hot bands. The large linewidth corresponds to a short lifetime in the ps range.

Infrared photodissociation of size selected internally excited ethylene clusters

Carbon dioxide clusters are generated in a supersonic molecular beam and size selected by scattering from a He beam. By analyzing the measured time-of-flight spectra as a function of the deflection angle, differential energy loss spectra for (CO2)2 — He are obtained which show a rotational rainbow structure with a maximal energy transfer of ΔE/E=0.4. This result is compatible with the slipped parallel structure of dimer but not with theT-shaped geometry. The scattering analysis is also used to derive information about the pressure dependence of cluster formation and the fragmentation by electron impact ionisation. The latter process leads preferably to the monomer product ion CO2+ with a small but finite probability for other ionic channels.

Collisional energy transfer and fragmentation of size selected CO2 clusters

Small ethylene clusters (C2H4)n are dissociated upon absorption of a C02-laser photon by exciting the υ7-mode of the monomer. The clusters are selected according to their size by scattering them from a helium beam. Since an appreciable amount of energy is transferred to the cluster during the collision, the laser photons interact with internally cold or hot clusters depending on whether the interaction is before or after the collision center. Measurements of the frequency and fluence dependences of the photodissociation cross section are carried out for cold and hot clusters from n=2 to n=6. The spectra of the cold clusters show the same shape and line- width for all cluster sizes investigated, while those of the hot clusters are characterized by large variations in shape and line- width. The very structured dimer spectrum is explained by the excitation of hot bands.

Infrared photodissociation of van der Waals complexes selectively prepared by molecular beam scattering

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

R. Sroka

Author Tools

Chat about Author

Papers

Infrared photodissociation of size selected internally excited ethylene clusters

Collisional energy transfer and fragmentation of size selected CO2 clusters

Infrared photodissociation of van der Waals complexes selectively prepared by molecular beam scattering