This chapter cites a gas phase sample that demonstrates molecules in continual motion, appropriate to its thermal energy. It describes the continual motion of the molecules as rotational energy, which is the kinetic energy associated with the tumbling motion of the molecules relative to an observer in the laboratory. The chapter explains that the transitions between individual rotational levels give rise to the rotational spectrum of the molecule and that the quantum states of a single molecule remain well-defined as long as the molecule is in isolation. However, the collision of a molecule with another species can change the rotational state. The definition of the spectrum is then in danger of being destroyed. It explains that the orientation of individuals in a solid state is usually fixed in space, and energy cannot be stored in the form of rotational motion, which is why rotational spectroscopy is carried out on gaseous samples at low pressure.

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In the past few years the field of hadron spectroscopy has seen renewed interest due to the pubblication, initially mostly from B-Factories, of evidences of states that do not match regular spectroscopy, but are rather candidates for bound states with additional quarks or gluons. A huge effort in understanding the nature of this new states and in building a new spectroscopy is ongoing. This report reviews the experimental and theoretical state of the art on heavy quarkonium exotic spectroscopy, with particular attention on the steps towards a global picture.

The fundamental principle of Fourier Transform Infrared (FTIR) spectroscopy is based on the vibration and rotation of atoms, and it has become a universal and widely used spectral methodology for the detection of internal molecular structures in a diverse range of fields. A considerable number of review articles pertaining to the applications of FTIR spectroscopy have been published in recent years. Nevertheless, a comprehensive summary of the application of FTIR spectroscopy in nanoparticles’ (NPs’) green synthesis has yet to be presented. In the present paper, we propose a series of case studies that demonstrate the application of FTIR spectroscopy in the analysis of metal and metal oxide NPs that have been synthesized using green synthesis processes. Furthermore, a summary is presented of the position of functional group bands in FTIR spectra that are responsible for the reduction, capping and stabilization of NPs. In this review, we explore the advantages and limitations of FTIR and propose methodologies for overcoming these challenges. We also present potential solutions for the analysis of complex FTIR spectra. The present summary is intended to serve as a compendium of information for researchers engaged in the field of green synthesis of NPs, utilizing FTIR spectroscopy as a research tool.

This chapter discusses photoionization, which is a process carried out in a gas phase that gives a large amount of energy to a molecule to make it ionize. It refers to the photoelectric effect in which radiation of a variable frequency is shone on the surface of an easily ionizable metal, such as an alkali. It also examines the energy required to ionize a hydrogen atom in a particular orbital and remove the electron from the influence of the Coulombic attraction of the nucleus. The chapter then clarifies how the ionization energy can be equated with the energy required to remove an electron from a particular molecular orbital of the molecule. It cites an experiment wherein the monochromatic radiation in the vacuum is focused onto a gaseous sample of molecules, which causes them to be ionized.

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All spectrometers rely on some mechanism to achieve spectral selectivity; common examples include gratings, prisms, and interferometers with moving mirrors. We experimentally demonstrated and validated a spectroscopic technique -- here dubbed Planck spectroscopy -- that measures the spectral emissivity of a surface using only a temperature-controlled stage and a detector, without any wavelength-selective optical components. Planck spectroscopy involves the measurement of temperature-dependent thermally emitted power, where the spectral selectivity is realized via the temperature- and wavelength dependence of Planck's law. We experimentally demonstrated and validated Planck spectroscopy in the mid infrared, for wavelengths from 3 to 13 um -- limited primarily by the bandwidth of our detector -- with resolution of approximately 1 um. The minimalistic setup of Planck spectroscopy can be implemented using infrared cameras to achieve low-cost infrared hyperspectral imaging and imaging ellipsometry.

This chapter discusses Raman spectroscopy, which is based on a light scattering effect and named after the Indian physicist C.V. Raman, who was the first to observe it after A. Smekal had theoretically predicted it in 1928. Raman spectroscopy provides a way for obtaining information on the rotational and vibrational levels of a homonuclear diatomic molecule, which is not possible using rotational and rotational–vibrational spectra. The chapter also mentions Rayleigh scattering wherein the great majority of photons are scattered in all directions without a change in energy. The chapter illustrates how a modern Raman spectrometer probes light from a monochromatic source directed at the molecular sample. The scattered light is then viewed at right angles to the incoming beam. Its component wavelength is resolved with either a monochromator or an interferometer.

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Vibrational spectroscopy, comprised of infrared absorption and Raman scattering spectroscopy, is widely used for label-free optical sensing and imaging in various scientific and industrial fields. The group theory states that the two molecular spectroscopy methods are sensitive to vibrations categorized in different point groups and provide complementary vibrational spectra. Therefore, complete vibrational information cannot be acquired by a single spectroscopic device, which has impeded the full potential of vibrational spectroscopy. Here, we demonstrate simultaneous infrared absorption and Raman scattering spectroscopy that allows us to measure the complete broadband vibrational spectra in the molecular fingerprint region with a single instrument based on an ultrashort pulsed laser. The system is based on dual-modal Fourier-transform spectroscopy enabled by efficient use of nonlinear optical effects. Our proof-of-concept experiment demonstrates rapid, broadband and high spectral resolution measurements of complementary spectra of organic liquids for precise and accurate molecular analysis.

This chapter defines vibrational motion, which is a periodic, concerted displacement of the nuclei in a molecule that leaves the centre of mass unaltered in laboratory space. It explains that the appropriate linear combination of the displacements of a nucleus from its equilibrium position is called the vibrational coordinate, which is used to describe a particular vibrational motion. It also mentions the polyatomic molecule. This has several distinct vibrational modes, while the diatomic molecule only has one. The chapter reviews two distinct contributions to energy: the kinetic part that arises from the motion of the nuclei and the potential part that comes from the compression or expansion of the bond from its equilibrium value. It highlights the form of the potential energy curve. This shows that molecular energy increases rapidly as the charged particles in the molecule experience strong repulsive forces.

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I review some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional $q\bar{q}$ mesons. I therefore begin by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section I discuss the opportunities that CEBAF can offer for the study of meson spectroscopy.

This tutorial provides the theoretical background, the principles, and applications of Electrochemical Impedance Spectroscopy (EIS) in various research and technological sectors. The text has been organized in 17 sections starting with basic knowledge on sinusoidal signals, complex numbers, phasor notation, and transfer functions, continuing with the definition of impedance in electrical circuits, the principles of EIS, the validation of the experimental data, their simulation to equivalent electrical circuits, and ending with practical considerations and selected examples on the utility of EIS to corrosion, energy related applications, and biosensing. A user interactive excel file showing the Nyquist and Bode plots of some model circuits is provided in the Supporting Information. This tutorial aspires to provide the essential background to graduate students working on EIS, as well as to endow the knowledge of senior researchers on various fields where EIS is involved. We also believe that the content of this tutorial will be a useful educational tool for EIS instructors.

This chapter covers spectroscopy involving the excitation of an electron from one state to another. It talks about how electronic transitions occur at longer wavelengths and are often seen in the visible state as the separation of electronic energy levels of open-shell molecules is typically small. It also mentions the characteristic potential energy curve of the electronic state that supports its own set of vibrational and rotational levels, emphasizing that electronic transitions involve a change of associated vibrational and rotational quantum numbers. The chapter defines the quantum numbers of the electronic wavefunction. It describes an electron as a fundamental particle with a very small mass, which requires a full quantum mechanical treatment.

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With the discovery of new states in recent years, interest in spectroscopy has revived. Recent experimental results in heavy flavour spectroscopy are reviewed, including charmonium, bottomonium, charmed mesons and baryons and bottom mesons.

This PrimeView illustrates some of the varied applications of laser-induced breakdown spectroscopy.

Solid state impedance spectroscopy enables the various contributions to the resistive and capacitive properties of electronically inhomogeneous condensed matter to be deconvoluted and characterized separately. The different contributions arise from electronically distinct areas in the sample, which can in an ideal case be represented each by one standard RC element. In the following, the basic principles of impedance spectroscopy, different types of experimental setups and several examples of experimental impedance data sets from nanostructured materials are reviewed and discussed. The data analysis and equivalent circuit modelling processes which are relevant for the application of this technique to nanomaterials are emphasized. The different dimensions and structure of nanomaterials as compared to macroscopic bulk samples leads to quite different and sometimes more complex data that require detailed analysis and advanced equivalent circuit models.

It is my great pleasure to inaugurate the new MDPI journal, [...]

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We propose a new Fourier-transform spectroscopy technique based on the rotational Doppler effect. The technique offers an application for optical vortex frequency combs, where each frequency component carries a unique amount of orbital angular momentum (OAM). Here, we emulate a vortex comb using a tunable single frequency laser and a collection of spiral phase plates, generating up to eleven distinct OAM modes. Unlike in traditional Fourier-transform spectroscopy based on the Michelson interferometer (linear Doppler effect), the spectral resolution of vortex-comb spectroscopy is not limited by the mechanical scan distance of the instrument but only by the measurement time. Although the spectrometer requires just one free-running frequency comb, the down-conversion scheme resembles dual-comb spectroscopy, leading to fast mode-resolved measurements.

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Multi-dimensional coherent spectroscopy (MDCS)1,2 is a powerful method for optical spectroscopy that has become an important tool for studying ultrafast dynamics in a wide range of systems. It is an optical analog of multidimensional nuclear magnetic resonance spectroscopy that enables the measurement of homogeneous linewidths in inhomogeneously broadened systems, many-body interactions, and coupling between excited resonances, all of which are not simultaneously accessible by any other linear or non-linear method. Current implementations of MDCS require a bulky apparatus and suffer from resolution and acquisition speed limitations that constrain their applications outside the laboratory3-5. Here we propose and demonstrate an approach to nonlinear coherent spectroscopy that utilizes three frequency combs with slightly different repetition rates. Unlike traditional nonlinear methods, tri-comb spectroscopy uses only a single photodetector and no mechanical moving elements to enable faster acquisition times, while also providing comb resolution. As a proof of concept, a multidimensional coherent spectrum with comb cross-diagonal resolution is generated using only 365 ms of data. These improvements make multidimensional coherent spectroscopy relevant for systems with narrow resonances (especially cold atomic and molecular systems). In addition the method has the potential to be field deployable for chemical sensing applications.

Abstract With more than 9000 papers published annually, X-ray photoelectron spectroscopy (XPS) is an indispensable technique in modern surface and materials science for the determination of chemical bonding. The accuracy of chemical-state determination relies, however, on a trustworthy calibration of the binding energy (BE) scale, which is a nontrivial task due to the lack of an internal BE reference. One approach, proposed in the early days of XPS, employs the C 1s spectra of an adventitious carbon layer, which is present on all surfaces exposed to air. Despite accumulating criticism, pointing to the unknown origin and composition of the adventitious carbon, this is by far the most commonly used method today for all types of samples, not necessarily electrically insulating. Alarmingly, as revealed by our survey of recent XPS literature, the calibration procedure based on the C 1s peak of adventitious carbon is highly arbitrary, which results in incorrect spectral interpretation, contradictory results, and generates a large spread in reported BE values for elements even present in the same chemical state. The purpose of this review is to critically evaluate the status quo of XPS with a historical perspective, provide the technique’s operating principles, resolve myths associated with C 1s referencing, and offer a comprehensive account of recent findings. Owing to the huge volume of XPS literature produced each year, the consequences of improper referencing are dramatic. Our intention is to promote awareness within a growing XPS community as to the problems reported over the last six decades and present a guide with best practice for using the C 1s BE referencing method.

This chapter highlights the principles behind infrared spectroscopy, focusing on the energy range of the infrared rays. These cause vibrational excitation of bonds within a molecule. It discusses stretching for higher energy and bending lower energy as the types of bond excitation. It also refers to the absorption of certain wavelengths of infrared radiation which can be correlated with the bending or stretching of specific types of bonds within a molecule. The chapter analyses the infrared spectra of organic molecules. These are complicated by bond oscillations in the whole molecule and affect the absorption of the incident radiation—such absorption gives rise to overtones and harmonics. It mentions spectra recorded in solution or as a neat substance, which show complexity due to hydrogen bonding with solvents or the presence of dimeric or polymeric associated species..

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The Tevatron experiments have each accumulated about 6 \ifb good data since the start of RUN II. This large dataset provided good opportunities for meson spectroscopy studies at the Tevatron. This article will cover the recent new $Υ(nS)$ polarization studies as well as exotic meson spectroscopy studies.

Abstract High-resolution fluorescence spectroscopy was used to characterize dissolved organic matter (DOM) in concentrated and unconcentrated water samples from a wide variety of freshwater, coastal and marine environments. Several types of fluorescent signals were observed, including humic-like, tyrosine-like, and tryptophan-like. Humic-like fluorescence consisted of two peaks, one stimulated by UV excitation (peak A) and one by visible excitation (peak C). For all samples, the positions of both excitation and emission maxima for peak C were dependent upon wavelength of observation, with a shift towards longer wavelength emission maximum at longer excitation wavelength and longer wavelength excitation maximum at longer emission wavelength. A trend was observed in the position of wavelength-independent maximum fluorescence ( Ex max Em max ) for peak C, with maximum at shorter excitation and emission wavelengths for marine samples than for freshwater samples. Mean positions of these maxima were: rivers Ex max Em max = 340 448 nm; coastal water Ex max Em max = 342 442 nm; marine shallow transitional Ex max Em max = 310 423 nm; marine shallow eutrophic Ex max Em max = 299 389 nm; and marine deep Ex max Em max = 340 438 nm. Differences suggest that the humic material in marine surface waters is chemically different from humic material in the other environments sampled. These results explain previous conflicting reports regarding fluorescence properties of DOM from natural waters and also provide a means of distinguishing between water mass sources in the ocean.

openAnalysis of the cometary spectra obtained at the Asiago 1.22m telescope, and calculation of their gas production rate relative to CN (0-0) molecular emission band.Analysis of the cometary spectra obtained at the Asiago 1.22m telescope, and calculation of their gas production rate relative to CN (0-0) molecular emission band

We extend the analysis of photon coincidence spectroscopy beyond bichromatic excitation and two-photon coincidence detection to include multichromatic excitation and multiphoton coincidence detection. Trichromatic excitation and three-photon coincidence spectroscopy are studied in detail, and we identify an observable signature of a triple resonance in an atom-cavity system.