Emission spectroscopy

Emission spectroscopy is an analytical technique used to identify and quantify the chemical composition of substances based on the light emitted by atoms or molecules when they are excited. When a substance is exposed to energy, such as heat or electromagnetic radiation, its electrons can be excited to higher energy levels. When these excited electrons return to their lower energy states, they release energy in the form of light (photons).

Angle-resolved photoemission spectroscopy (ARPES) is a powerful experimental technique used to study the electronic structure of materials. It provides information about the energy and momentum of electrons in a solid. The technique involves the following key steps: 1. **Photon Emission**: ARPES utilizes high-energy photons (typically from a synchrotron radiation source or lasers) to irradiate a material. When these photons interact with the material, they can eject electrons from the surface.

Atomic Emission Spectroscopy (AES) is an analytical technique used to identify and quantify elements in a sample based on the light emitted by atoms. The process involves the excitation of atoms, which causes them to emit light at characteristic wavelengths. This emitted light is then analyzed to determine the composition of the sample.

The Balmer series is a set of spectral lines corresponding to the transitions of electrons in hydrogen atoms from higher energy levels to the second energy level (n = 2). This series is part of the hydrogen emission spectrum and consists of visible light wavelengths.

Chemiluminescence is the production of light as a result of a chemical reaction. Unlike fluorescence or phosphorescence, where light is emitted after absorbing energy (usually from light), chemiluminescence generates light directly from the reaction itself. This phenomenon can occur in various biological and chemical processes. A common example of chemiluminescence is the light produced by fireflies.

Coronal radiative losses refer to the energy that is radiated away by the solar corona, which is the outermost layer of the Sun's atmosphere. The corona is extremely hot, with temperatures reaching millions of degrees Celsius, and it emits energy primarily in the form of X-rays and ultraviolet radiation. In astrophysics, particularly in the study of stellar atmospheres, radiative losses occur when hot plasma (such as that found in the corona) cools by emitting photons.

Einstein coefficients are a set of quantifiable parameters that describe the interaction of atoms or molecules with electromagnetic radiation. They are critical in the field of quantum mechanics and spectroscopy and were introduced by Albert Einstein in his seminal works on the theory of radiation in the early 20th century.

Equivalent width is a measure used in spectroscopy to quantify the strength of spectral lines, such as absorption or emission features in a spectrum. It provides a way to describe how much of the continuum flux is absorbed or emitted by a feature, relative to the continuum level.

The Evershed effect refers to the observed radial outflow of plasma from sunspot regions in the solar atmosphere, particularly in the photosphere and chromosphere. Named after the British astronomer F. W. Evershed, who described it in the early 20th century, this effect is characterized by the detection of a blue shift in spectral lines in sunspot penumbrae, indicating that material is moving outward at high speeds.

Gaussian broadening is a technique used in various fields such as spectroscopy, astrophysics, and materials science to smooth or enhance the representation of data. The process involves convolving a given data set or signal with a Gaussian function (a bell-shaped curve), which effectively broadens the features in the data.

Glow-discharge optical emission spectroscopy (GD-OES) is an analytical technique used for the elemental analysis of solid materials. It combines two main processes: glow discharge and optical emission spectroscopy. Here's a brief overview of how it works and its applications: ### How It Works 1. **Glow Discharge**: - A glow discharge is established between two electrodes in a low-pressure gas (such as argon).

The Hydrogen line, also known as the 21-centimeter line, refers to the specific wavelength (21 centimeters) of electromagnetic radiation emitted by neutral hydrogen atoms. This emission occurs when the electron in a hydrogen atom transitions between two hyperfine levels of its ground state. The 21-cm line is significant in astronomy because it is a key spectral line used for studying the distribution and structure of hydrogen in the universe.

The hydrogen spectral series refers to the specific wavelengths of light emitted or absorbed by hydrogen atoms when electrons transition between different energy levels. These transitions occur when an electron absorbs energy and moves to a higher energy level (excitation) or when it releases energy and falls back to a lower energy level (emission). The emitted or absorbed light appears in distinct spectral lines, grouped into series corresponding to different electron transitions.

Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), also known as Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), is an analytical technique used for elemental analysis of various materials, including solids, liquids, and gases. Here's a brief overview of how it works and its applications: ### Principle: 1. **Induction of Plasma**: An inductively coupled plasma is created using a high-frequency (usually radiofrequency) electric field.

Inverse photoemission spectroscopy (IPES) is a powerful experimental technique used to study the electronic states of materials, particularly surfaces and interfaces. In contrast to traditional photoemission spectroscopy (PES), which involves the excitation of electrons from a material by incident photons (measuring the emitted electrons), IPES involves the injection of electrons into a material, where these electrons can excite the material and subsequently emit photons.

Isotopic shift refers to the change in the energy levels of atomic or molecular states that occurs due to the substitution of an atom in a molecule with one of its isotopes. This shift can be observed in various spectroscopic techniques, such as infrared (IR) spectroscopy, Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The isotopic effect arises because isotopes of the same element have different masses, which affects vibrational frequencies, rotational transitions, and other properties of molecules.

Laser-based angle-resolved photoemission spectroscopy (ARPES) is an advanced experimental technique used primarily in condensed matter physics to investigate the electronic structure of materials. It combines the principles of angle-resolved photoemission with the high energy and specificity offered by lasers. ### Key Features of Laser-based ARPES: 1. **Photoemission Principle**: In ARPES, photons are used to excite and eject electrons from a material's surface.

The Lyman-alpha line is a specific spectral line in the ultraviolet part of the electromagnetic spectrum. It corresponds to a transition of an electron in a hydrogen atom from the second energy level (n=2) to the first energy level (n=1). This transition emits a photon with a wavelength of approximately 121.6 nanometers (nm).

Lyman continuum photons are a specific type of ultraviolet (UV) photons that have energies high enough to ionize hydrogen atoms. This range of photon energies corresponds to wavelengths shorter than the Lyman series limit, which is approximately 91.2 nanometers (nm). More specifically, the Lyman continuum refers to the wavelength range below 91.

The Lyman series refers to a series of spectral lines corresponding to electronic transitions in the hydrogen atom. Specifically, it consists of transitions where an electron moves from a higher energy level (n ≥ 2) down to the ground state (n = 1). These transitions emit ultraviolet light, and the wavelengths of the emitted photons can be calculated using the Rydberg formula.

Microturbulence is a term primarily used in astrophysics and astronomy, specifically in the study of stellar atmospheres and the behavior of gases in space. It refers to small-scale, turbulent motions within a stellar atmosphere or in the interstellar medium that can affect the interpretation of spectral lines. In the context of a star's atmosphere, microturbulence is thought to be a form of turbulence that occurs on very small spatial scales, leading to localized and chaotic movements of gas.

Nano-Angle-Resolved Photoemission Spectroscopy (Nano-ARPES) is an advanced experimental technique in condensed matter physics used to study the electronic structure of materials at the nanoscale. It combines the principles of angle-resolved photoemission spectroscopy (ARPES) with nanoscale spatial resolution.

Particle-induced X-ray emission (PIXE) is an analytical technique used to determine the elemental composition of various materials. It involves bombarding a sample with high-energy particles, typically protons or alpha particles, which causes the emission of characteristic X-rays from the atoms in the sample. ### Key Steps of the PIXE Process: 1. **Sample Irradiation**: The sample is hit by a beam of high-energy particles.

Photoemission spectroscopy (PES) is an analytical technique used to investigate the electronic properties of materials. It involves the absorption of photons (light) by a sample, which results in the emission of electrons. The primary goal of PES is to study the energy and distribution of these emitted electrons, providing valuable insights into the material's electronic structure. ### Basic Principles: - **Excitation:** A sample is irradiated with high-energy photons, typically from ultraviolet or X-ray sources.

In the context of spectroscopy, "principal series" refers to a specific set of spectral lines that arise from the electronic transitions of atoms or ions, particularly in the hydrogen atom and hydrogen-like systems. These transitions occur between different energy levels characterized by principal quantum numbers. For hydrogen, the principal series typically involves transitions where an electron moves from higher energy levels (n ≥ 2) down to the first energy level (n = 1).

The Rydberg–Ritz combination principle is a concept in the field of spectroscopy that relates to the spectral lines of atoms, particularly hydrogen. It was formulated in the early 20th century based on the work of physicists Johannes Rydberg and Walther Ritz.

The term "Sharp series" typically refers to a mathematical concept that may not be widely known as a specific series. However, it could relate to several contexts where "sharp" indicates precision or a specific property of a series.

The Struve-Sahade effect refers to an astrophysical phenomenon that occurs in certain binary star systems, particularly in cases where one of the stars is a giant star. It describes the observational changes in the spectra of the components of the binary system due to the presence of the giant star's extended atmosphere, which can influence the absorption lines seen in the spectrum.

The term "Swan band" can refer to two distinct concepts depending on the context: 1. **Music Context**: The Swan Band might refer to a specific musical group or ensemble known for their particular style or repertoire. However, there isn't a widely recognized band by that name as of my last knowledge update in October 2023.

Two-photon photoelectron spectroscopy (TPPE) is a sophisticated technique used in the field of surface science and condensed matter physics to investigate the electronic properties of materials. This technique enables the study of the electronic structure and dynamics of materials at various interfaces, such as solid-vacuum, solid-liquid, or solid-gas interfaces.

Ultraviolet Photoelectron Spectroscopy (UPS) is an analytical technique used to study the electronic structure of materials, particularly surfaces and thin films. It is based on the photoelectric effect, where ultraviolet light is used to irradiate a sample, resulting in the emission of photoelectrons from the material. ### Key Features of UPS: 1. **Principle**: UPS involves shining UV light onto a sample, which causes electrons to be ejected.

Vibrational energy relaxation refers to the process by which vibrational energy, which is the energy associated with the vibrational motion of atoms within a molecule, dissipates or transitions to other forms of energy, typically in a condensed phase or gas. This process is significant in various fields, including physical chemistry, materials science, and biophysics, as it plays a critical role in energy transfer mechanisms, chemical reactions, and the behavior of complex systems.

Wavelength-dispersive X-ray spectroscopy (WDX or WDS) is an analytical technique used to determine the elemental composition of materials. It is widely employed in various fields such as materials science, geology, and semiconductor research. WDX relies on the principle of X-ray fluorescence, where a sample is irradiated with a beam of X-rays, causing the atoms in the sample to emit secondary X-rays characteristic of their elemental composition.

X-ray emission spectroscopy is a technique used to analyze the elemental composition of materials by measuring the X-rays emitted from a sample when it is excited by a source of X-rays or other high-energy radiation. This method provides information about the types and quantities of elements present in the sample. ### Key Principles: 1. **Excitation**: When a sample is irradiated with high-energy photons (such as X-rays), inner-shell electrons may be ejected from atoms in the sample.

X-ray photoelectron spectroscopy (XPS) is an analytical technique used to study the surface chemistry of materials. It involves irradiating a material with X-rays, which causes the ejection of photoelectrons from the surface atoms. By measuring the kinetic energy of these emitted photoelectrons, XPS can provide information about the elemental composition, chemical state, and electronic state of the elements present in the material.