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What happens during photoionization?
photo-ionization, the interaction of electromagnetic radiation with matter resulting in the dissociation of that matter into electrically charged particles. The simplest example, the photoelectric effect (q.v.), occurs when light shines on a piece of metal, causing the ejection of electrons.
What is photoionization in biology?
When light energy is absorbed by a chlorophyll molecule its electrons gain energy and move to higher energy levels in the molecule (photoexcitation). Sufficient energy ionises the molecule, with the electron being ‘freed’ leaving a positively charged chlorophyll ion. This is called photoionisation.
What is solar photoionization?
The Sun’s radiation causes photoionisation: Photoionization is a process in which a photon ejects one or more electrons from a neutral atmospheric particle (atom or molecule) turning it into a charged particle – an ion. The Sun, solar radiation and Earth seen from the International Space Station.
What is meant by auto ionization?
: a process by which an excited atom becomes ionized and goes to a lower energy state by emitting one of two or more excited electrons that together possess energy exceeding the atom’s ionization energy especially : such a process yielding an electron having an energy equivalent to that of a photon of optical …
What does a photoionization detector measure?
A PID uses an ultraviolet (UV) light source to break down VOCs in the air into positive and negative ions. The PID then detects or measures the charge of the ionized gas, with the charge being a function of the concentration of VOCs in the air.
What is photosynthesis Aqa definition?
Plants, unlike animals, can make their own food. They do this using a process called photosynthesis . During photosynthesis, plants produce glucose from simple inorganic molecules – carbon dioxide and water – using light energy.
What is autoionization and give an example?
Autoionization is a process by which an atom or a molecule in an excited state spontaneously emits one of the outer-shell electrons, thus going from a state with charge Z to a state with charge Z + 1, for example from an electrically neutral state to a singly ionized state.
What is the autoionization of water?
– [Instructor] The autoionization of water refers to the reaction of water molecules to form two ions, the hydronium ion, which is H3O+, and the hydroxide ion, which is OH-. In the reaction, the base takes an H+ ion from the acid and these two electrons are left behind on this oxygen.
What is a limitation of some photoionization detectors?
Limitations and Concerns The PID may give false positive readings for water vapor. Rain may also affect performance. High humidity can cause lamp fogging and decreased sensitivity.
What does the MultiRAE detect?
RAE Systems’ MultiRAE multigas monitors give you the ability to detect and monitor up to six gases for personal protection and industrial leak detection applications. MultiRAE can test for VOCs in a range of 0-5000 ppm, combustibles, and a range of toxic threats, plus monitor sufficient oxygen levels.