Photonic Solutions for Chemistry

Andor’s modular spectroscopy platforms are designed to tackle a wide range of photonics application challenges spanning Chemistry, Catalysis, Materials Science, Analytical Chemistry, Photochemistry and Photophysics.

Optical spectroscopic techniques can be employed to non-invasively study changes in composition of chemicals or materials. Chemical reaction products or transient behaviours can be probed by fast reaction monitoring or more intricate pump-probe Raman or absorption spectroscopy. In analytical chemistry, atomic and molecular spectroscopic signatures can be used to identify and quantify specific chemical species, with a myriad of real-world applications.

Furthermore, Andor’s Optistat range of Optical Cryostats can be integrated into spectroscopy set-ups to provide precision control of sample temperatures from 4 K up to 500 K.

Applications

Reaction Monitoring and Catalysis

The spectroscopic study of the transformation processes of chemical species (reactants) to new chemical species (products) with different structure/arrangement/properties.

Chemical reaction types include synthesis, decomposition, displacement (a more active element displaces another less active element from a compound), redox and isomerisation.

Photochemistry and Photophysics

The study of the effect of light absorption (typically in the UV-IR region) by chemical species, resulting in chemical or physical property changes.

It includes the analysis of the transformation processes in molecules, specifically studying their transient excited states /energy transfer processes, as characterised through a Jablonski diagram, on timescales ranging from millisecond to picoseconds.

Analytical Chemistry

Atoms and molecules have unique spectra, meaning that optical spectroscopy can be used to non-invasively detect, identify and quantify substances.

Furthermore, vibrational techniques such as Raman spectroscopy, which typically can yield very fine fingerprint spectra, can discriminate and measure chemical species with very high specificity.

Process Control and Quality Control

The concepts of reaction monitoring and analytical chemistry combine under industrial settings in terms of the use of optical spectroscopy for process control.

Furthermore, spectroscopy also finds widespread use in quality control and to determine authenticity.

Techniques

Raman Spectroscopy

A laser scattering-based spectroscopy technique which non-invasively probes the molecular composition and structure of samples. It can be used to identify chemical species throughout reactions, or to monitor reaction rates by looking at the intensity of spectral features specific to reactants, catalysts and products. Raman signal is typically quite weak, but techniques like Resonance Raman exploit specific light absorption properties of molecules over a given wavelength range to provide significant Raman signal enhancement.

For organic species, Raman signal competes with fluorescence from the sample - a near-infrared laser or UV laser (with wavelength outside the absorption range of the molecule) can be used to greatly minimise or supress unwanted fluorescence contribution.

Absorption Spectroscopy

If light of impinges on an atom or molecule in its ground state, photons of specific energies (wavelengths) are absorbed to promote electrons to an excited state. The absorbed photon energy is determined specifically by the gap between ground and excited state of that particular atom or molecule. Furthermore, by measuring the amount of light absorbed, a quantitative determination of the amount of analyte element present can be made. UV-Vis-NIR spectroscopy is useful to characterise the absorption, transmission, and reflectivity of a variety of materials such as pigments, biological, coatings, windows, filters, or analyse the dynamics of chemical reactions.

Transient Spectroscopy

Transient spectroscopy encompasses a powerful set of techniques for probing and characterizing the electronic and structural properties of short-lived excited states (transient states) of photochemically or photophysically relevant molecules. These states are accessed upon absorption of photons and essentially represent higher energy forms of the molecule, differing from the lowest energy ground state in the distribution of electrons and/or nuclear geometry.

A battery of complimentary pump-probe techniques is often used in laser spectroscopy laboratories, including Time-Resolved Resonance Raman (TR3) Spectroscopy, Time-Resolved Emission Spectroscopy and Time-Resolved Absorption (Transient Absorption) Spectroscopy.

Luminescence Spectroscopy

Luminescence spectroscopy is used for a large variety of applications including for example the study of metal complexes, organic LEDs (OLEDs), quantum dots, cell dynamics, stand-off detection of chemical compounds (e.g. explosives) or measurement of scintillator properties. Modalities of luminescence spectroscopy include fluorescence/phosphorescence, cathodoluminescence and chemiluminescence.

Luminescence spectroscopy can be used to measure the concentration of a compound, as the intensity is linearly proportional to the concentration of the luminescent molecule. Pump-probe luminescence spectroscopy can also provide information on the lifetime of the excited energy levels in molecules or atoms. In the context of the development of fluorescence dyes for biological applications, fluorescence spectroscopy can be use do determine the efficiency of the fluorescence emission process after initial excitation, i.e. the "fluorescence quantum yield".

Micro-Spectroscopy

Micro-Spectroscopy covers a very wide range of spectroscopy modalities with the common character that the spectroscopic measurement is made on the microscopic scale.

Andor spectroscopy systems are routinely used for Raman-based techniques including Micro- Raman and Fluorescence/Photoluminescence, Diffuse Scattering micro-spectroscopy and Multiphoton micro-spectroscopy.

Optical Emission Spectroscopy

OES involves applying an electrical charge to the sample which vaporizing a small amount of material. A discharge plasma with a distinct spectroscopic signature is created, from which the elemental breakdown of the sample can be determined. OES is a rapid method that can be used to determine the elemental composition of a variety of metals and alloys.

OES usually involves collecting highly resolved spectroscopic signature across the Ultra-violet and Visible region of the electromagnetic spectrum.

X-Ray Spectroscopy

X-ray spectroscopy is an umbrella term for several spectroscopic techniques for characterization of materials by using X-ray excitation, including the likes of X-Ray Absorption (XAS, XANES, EXAFS) and Emission (XES). These modalities are used to probe the electronic structure of atoms or the atomic chemical make-up of a sample. Analysis of the X-ray emission spectrum produces qualitative and quantitative information about the elemental composition of the specimen.

They can provide information on the oxidation state of species, but also find applications for in situ and in operando studies of functional systems (enclosed by opaque structures).

X-Ray Diffraction & Scattering

X-ray diffraction and scattering techniques measure the scattered intensity and/or energy of an X-ray beam to provide detailed information about the crystal structure, chemical composition, and physical properties of materials and thin films. They are non-destructive analytical techniques which are based on observing the scattered intensity of an X-ray beam hitting a sample as a function of incident and scattered angle, polarization, and wavelength or energy. Scattering techniques include Wide-angle X-ray diffraction (WAXD), Small-angle X-ray scattering (SAXS) and Wide-angle X-ray scattering (WAXS).

$X-Ray Diffraction$

Fluorescence Correlation Spectroscopy

Time correlated statistical analysis of fluctuations in fluorescence intensity. This is commonly utilised to provide information on the concentration & size fluctuations of molecules in solution over time. A common application of FCS is the analysis of the concentration fluctuations of fluorescent particles/molecules in solution, in which the fluorescence emitted from a very tiny confocal space in solution is observed. This tiny, focused laser beam waist would typically contain only a small number of fluorescent molecules. Analysis yields the average number of fluorescent particles and average diffusion time when the particle is passing through the probed space, ultimately allowing both concentration and size of the particle to be determined. Such parameters can be important in chemistry and biophysics research.

Products

Learning Centre Resources

Obtaining Raman Spectra in NIR using InGaAs Detectors

Obtaining Raman spectra especially in reaction monitoring is often plagued by fluorescence either from molecular fluorophores or from particulates, e.g. Pd nanoparticles, in the...

Quantitative Monitoring of Biphasic Reactions using Flow Systems by Raman Spectroscopy

Biphasic reactions offer tremendous opportunities in industrial chemical syntheses due to the ease at which the phases and hence reagents can be separated, thereby avoiding ener...

Raman Spectroscopy: Overcoming Difficulties Presented by Challenging Samples

Raman spectroscopy combines the information density of vibrational spectroscopy with the experimental flexibility of optical spectroscopy. It provides label-free analysis of sam...

Transient Spectroscopy: Pump-Probe Techniques for Characterising the Excited States of Molecules

Transient spectroscopy encompasses a powerful set of techniques for probing and characterizing the electronic and structural properties of short-lived excited states (transient ...

Femtosecond Fluorescence Spectroscopy based on the Optical Kerr Effect

The period of vibrational motions in molecules (10 – 300 femtoseconds(fs)) sets a lower limit for the time scale of chemical processes [1, 2]. Being able to measure the dy...

Optically Probing Surface Phonons using Surface Specific Vibrational Spectroscopy

Terminating a metal oxide produces a layer of under coordinated surface atoms. In vacuum this undercoordination causes substantial surface relaxation: interatomic distances devi...

A soft X-ray spectrometers at the Advanced Light Source (ALS)

When electrons in materials are excited by x-rays, the material can return to the ground state by re-emitting photons and electrons. Analyzing the energy of emitted photons and ...

Tip Enhanced Raman Spectroscopy

Label-free chemical analysis of nanostructures Tip-Enhanced Raman Spectroscopy (TERS) is developing into a powerful technique for the characterization of bio-molecules at the n...

Raman Spectroscopy - A New Dawn in Clinical Diagnostics

Raman spectroscopy (RS) has shown enormous potential in sensitive and specific elucidation of latent information of a diverse array of pathophysiological conditions. This talk h...

Optofluidic Raman Spectroscopy for Chemical Analysis and Raman Spectroscopy Bio-Sensor for Tissue Analysis

Abstract Raman spectroscopy is a powerful spectroscopic tool in the field of bio-chemical analysis for chemical fingerprinting. The ability of this technique to achieve multi-c...

Size and Shape Dependent Photoluminescence Properties of Diamondoids and Cyclohexane

We present photoluminescence spectra of a new class of carbon nanocrystals called diamondoids, and of cyclohexane. For this study, specific isomers of the five smallest members ...

Customer Publications

Author	Title	Year
Medagedara et al	Decorrelated singlet and triplet exciton delocalization in acetylene-bridged Zn-porphyrin dimers	2024
Ishikawa et al	Surface sulfurization of amorphous carbon films in the chemistry of oxygen plasma added with SO2 or OCS for high-aspect-ratio etching	2024
Liu et al	Light-driven eco-evolutionary dynamics in a synthetic replicator system	2024
Bora et al	New Multifunctional Bipyrimidine-Based Chromophores for NLO-Active Thin-Film Preparation	2024
Wang et al	Analysis of SF₆ decomposed products by fibre-enhanced Raman spectroscopy for gas-insulated switchgear diagnosis	2024
Wang et al	Intercomparison of NO3 under Humid Conditions with Open-Path and Extractive IBBCEAS in an Atmospheric Reaction Chamber	2023
Xu et al	In Situ Confocal Raman Microscopy of Redox Polymer Films on Bulk Electrode Supports	2023
Ratschmeier et al	Influence of interfacial water and cations on the oxidation of CO at the platinum/ionic liquid interface	2023
O’Neill et al	Photophysical and electrochemical properties of meso-tetrathien-2′-yl porphyrins compared to meso-tetraphenylporphyrin	2023
Wallace et al	Low-Frequency Raman Spectroscopy of Pure and Cocrystallized Mycophenolic Acid	2023
Raics et al	Photocycle alteration and increased enzymatic activity in genetically modified photoactivated adenylate cyclase OaPAC	2023
Ucker et al	Surface modification of T-Nb₂O₅ with low-crystallinity Nb2O5 to enhance photocatalytic degradation of rhodamine B	2023
Fayad et al	Adsorption of Nickel Ions on the γ-Alumina Surface: Competitive Effect of Protons and Its Impact on Concentration Profiles	2023
Rossi et al	In Situ Observation of Chemical Reactions at Buried Solid/Solid Interfaces in Coextruded Multilayer Polymer Films	2023
Zheng et al	Chain Conformation and Exciton Delocalization in a Push–Pull Conjugated Polymer	2023

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