Photoionization — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Q: What is the formula for Photoionization?

The formula or notation for Photoionization is: A + hν → A⁺ + e⁻

Formula / Notation	A + hν → A⁺ + e⁻
Also Known As	Photoelectric effect (atomic), photoemission, photon-induced ionization

What is Photoionization?

Photoionization (photoelectric effect in atoms) is the process in which a photon of sufficient energy is absorbed by an atom or molecule, ejecting an electron and creating a positive ion. The photon energy must exceed the ionization energy (IE) of the atom. The excess energy goes into kinetic energy of the ejected electron. Photoionization is the basis of photoelectron spectroscopy (PES) and photoionization mass spectrometry.

Formula & Notation

A + hν → A⁺ + e⁻

Other Names / Synonyms: Photoelectric effect (atomic), photoemission, photon-induced ionization

Properties & Characteristics

Condition: hν ≥ IE (photon energy ≥ ionization energy). Einstein photoelectric equation: KE = hν − IE. Photon sources: UV (UV-PES), X-ray (XPS). Threshold frequency: ν_t = IE/h. Photoionization cross-section: element and energy dependent. Products: ion (A⁺) and free electron (e⁻).

Uses & Applications

Photoelectron spectroscopy (PES/UPS) for electronic structure. X-ray photoelectron spectroscopy (XPS) for surface analysis. Photoionization mass spectrometry. Atmospheric photoionization (UV radiation ionizes molecules). Photoionization detectors (PID) for VOC monitoring. Astrophysical plasma modeling.

Safety Information

UV and X-ray radiation hazardous to eyes and skin. High-intensity UV sources: proper shielding required. XPS uses X-rays: radiation protection needed. Photoionized gases may be reactive.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Photoionization

Formula A + hν → A⁺ + e⁻

Index All "P" terms

Synonyms Photoelectric effect (atomic), photoemission, photon-induced ionization

Frequently Asked Questions

What is Photoionization?

Photoionization (photoelectric effect in atoms) is the process in which a photon of sufficient energy is absorbed by an atom or molecule, ejecting an electron and creating a positive ion. The photon energy must exceed the ionization energy (IE) of the atom. The excess energy goes into kinetic energy of the ejected electron. Photoionization is the basis of photoelectron spectroscopy (PES) and photoionization mass spectrometry.

What is Photoionization used for?

Is Photoionization hazardous?

What is the formula for Photoionization?

More "P" Terms

P-type Semiconductor Pairing Pairing Energy Palladium Pd Parachor [P] = M(γ)^(1/4) / (ρ_L - ρ_V) Paramagnetic χ_m > 0; unpaired electrons; μ = √(n(n+2)) BM (n = unpaired electrons) Paramagnetism Partial Ionic Character % ionic = (1 - e^(-Δχ²/4)) × 100% Partial Pressure Partial Pressure p_i = x_i × P_total; P_total = Σp_i Particulate Matter Parts Per Million ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

View all "P" terms →