Terms related to molecular spectroscopy [和分子光譜術相關的專有名詞]
[A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]
Ab initio
calculation 

Adiabatic
process 

AM1, Austin method 1, a semiemprical procedure 

Angular
momentum 

Anharmonicity 

Astronomical
Spectroscopy Energy from celestial objects is used to analyze their chemical composition, density, pressure, temperature, magnetic fields, velocity, and other characteristics. There are many energy types (spectroscopies) that may be used in astronomical spectroscopy. 

Atomic
Absorption Spectroscopy Energy absorbed by the sample is used to assess its characteristics. Sometimes absorbed energy causes light to be released from the sample, which may be measured by a technique such as fluorescence spectroscopy. 

Atomic
units 電量以e (elementary charge) 的倍數表示。Elementary charge, e = 1.602 x 10^{19} C 長度以a_{0} (Bohr radius) 的倍數表示。Bohr, a_{0} = 4πε_{0}•ħ^{2} / m_{e}e^{2} = 0.5292 Å = 5.292 x 10^{11} m Action (energy x time)以ħ 的倍數表示。Planck’s constant / 2π = 1.055 x 10^{34} J•s 能量以hartree的倍數表示。E_{h} = ħ^{2} / m_{e}a_{0}^{2} = 2hcR_{¥} = 4.369 x 10^{18} J。 

Attenuated
Total Reflectance Spectroscopy This is the study of substances in thin films or on surfaces. The sample is penetrated by an energy beam one or more times and the reflected energy is analyzed. Attenuated total reflectance spectroscopy and the related technique called frustrated multiple internal reflection spectroscopy are used to analyze coatings and opaque liquids. 

Auger
spectroscopy 

Autoionization 

Autoionization state 

BornOppenheimer
(BO) approximation 

Boson, A boson is a particle with integral spin (including zero), e.g. ^{2}H (I = 1), αparticle (I = 0). 

Bracket
notation 

Branches O branch: lines arising from J → J2 (Raman spectra) P branch: lines arising from J → J1 (infrared and Raman spectra) Q branch: lines arising from J → J (if allowed) R branch: lines arising from J → J+1 (infrared and Raman spectra) S branch: lines arising from J → J+2 (Raman spectra) 

CIS,
Configuration interaction singles 

Coriolis
force 

Degeneracy 

Doppler width, δω δω_{D} = (ω_{0}/c){8kT•ln2/m}^{1/2} = (2ω_{0}/c){2RT•ln2/M}^{1/2} δν_{D} = 7.16 x 10^{7}ν_{0}{T/M}^{1/2} [s^{1}] (a)
VUV: For the Lyman α line (2P → 1S transition in H atom) in a
discharge with (b)
VIS: For the sodium D line (3P → 3S transition in Na atom) in a
sodium vapor cell at temperature T = 1000 K, M = 23, λ = 5891 Å, ν_{0}=
5.1 x 10^{14} s^{1}, 

Duschinsky
effect 

Electron
Paramagnetic Spectroscopy This is a microwave technique based on splitting electronic energy fields in a magnetic field. It is used to determine structures of samples containing unpaired electrons. 

Electron
spectroscopy 

Fermi’s
golden rule 

Fluorescence 

Fourier
Transform Spectrosopy This is a family of spectroscopic techniques in which the sample is irradiated by all relevant wavelengths simultaneously for a short period of time. The absorption spectrum is obtained by applying a mathematical analysis to the resulting energy pattern. 

FranckCondon
factor (integral, principle) [webpage FC] 

Gammaray
Spectroscopy Gamma radiation is the energy source in this type of spectroscopy, which includes activation analysis and Mossbauer spectroscopy. 

Gaussian
atomic orbital 

HeI
& HeII light sources
(氦I與氦II紫外光光源) 

Holeburning
spectroscopy (燒孔光譜術) [webpage HB] 

HOMO, highest occupied molecular orbital 

Hyperconjugation
(超共軛) 

Infrared
Spectroscopy The infrared absorption spectrum of a substance is sometimes called its molecular fingerprint. Although frequently used to identify materials, infrared spectroscopy also may be used to quantify the number of absorbing molecules. 

Intensity
stealing (or borrowing) 

Intermolecular
forces (a) Ionion interaction (between charged species): V µ 1/R (b) Iondipole interaction (between ions and polar molecules): V µ 1/R^{2} (c) Dipoledipole interaction (between two polar molecules): V µ 1/R^{3}in a solid (when molecules are not rotating) but as V µ 1/R^{6} in a fluid (in which molecules rotate). (d) dipoleinduced dipole interaction (between a polar molecule and a polarizable molecule [which may or may not be polar]): V µ 1/R^{6}. (e) induced dipoleinduced dipole interaction (between a polarizable molecule and a polarizable molecule [which may or may not be polar]): V µ 1/R^{6}. This is referred as dispersion force or London force. The typical magnitude of the potential energy of the dispersion interaction is about 2 kJ mol^{1}. 

Internal
conversion 

Intersystem
crossing 

Ionization energy (adiabatic and vertical) [webpage IE] 

Infrared
spectroscopy 

Infrared
photoinduced Rydberg Ionization (IRPIRI)
spectroscopy 

Jablonski
diagram 

JahnTeller
theorem 

JWKB, (JefferysWentzelKramersBrillouin), s semiclassical approximation to quantum mechanics 

Kasha’s
law 

Koopmans’
theorem 

Laser
Spectroscopy Absorption spectroscopy, fluorescence spectroscopy, Raman spectroscopy, and surfaceenhanced Raman spectroscopy commonly use laser light as an energy source. Laser spectroscopies provide information about the interaction of coherent light with matter. Laser spectrocopy generally has high resolution and sensitivity. 

Lorentzian
line shape a / {[(νν_{mn})^{2}+(τ_{n}^{1}+τ_{m}^{1})^{2}]/16π^{2}}, where τ_{n} and τ_{m} are the average lifetimes of states n and m, ν_{mn} is the frequency, and a is a constant characteristic of the transition. The general form of a Lorentzian line shape is a / [(νν_{0})^{2}+b^{2}]. For the Lorentzian line shape, the maximum occurs at ν = ν_{0} and equals a/b^{2}. For the WeisskopfWigner shape, b = (τ_{n}^{1}+τ_{m}^{1})^{2}]/4π. If state n is the ground state, thenτ_{n} = ¥ and the width of the spectral line measures the uncertainty DE_{m} is the energy of the excited state. Then, DE_{m}•τ_{m} = ħ/2. 

LUMO, lowest unoccupied molecular orbital 

Mass analyzed threshold ionization (MATI)
spectroscopy [webpage MATI]


Mass
Spectrometry A mass spectrometer source produces ions. Information about a sample may be obtained by analyzing the dispersion of ions when they interact with the sample, generally using the masstocharge ratio. 

Moment of inertia, I_{e} =μR_{e}^{2}, (at equilibrium) 

Morse
potential 

Mulliken
population analysis 

Multiphoton
ionization (MPI) spectroscopy 

Multiplex or
FrequencyModulated Spectroscopy In this type of spectroscopy, each optical wavelength that is recorded is encoded with an audio frequency containing the original wavelength information. A wavelength analyzer can then reconstruct the original spectrum. 

Onecolor resonant twophoton
ionization (1CR2PI) spectroscopy
[1CR2PI] 單色共振二光子游離光譜術, 詳細敘述請參看另一網頁。 

Orthohydrogen Hydrogen with parallel spins (rotational states with odd J values). 

Oscillator
strength The oscillator strength f of a transition is a measure of its intensity. For strongly allowed transitions f is close to 1; for symmetryforbidden transition f is close to 10^{5}. 一個躍遷過程的f 可反映至光譜線的強度。 

Parabolic potential energy, V = (1/2)kx^{2}  
Parahydrogen Hydrogen with paired nuclear spins (rotational states with even J values). 

Polaron A polaron is a defect in an ionic crystal that is formed when an excess of charge at a point polarizes the lattice in its vicinity. 

Photoelectron (PE) spectroscopy (光電子光譜術) 光電子光譜術，當分子吸收光子的過程中，若光子的能量(E_{hv})高過於分子的游離能(E_{I})時，分子即被游離(即所謂的光電效應)成離子，同時電子也被釋放出來。多餘的能量E_{excess} = E_{hv} E_{I} = 離子態分子的動能(E_{k}^{ion})+離子態分子的內能(E_{i}^{ion})+電子的動能(E_{k})，光電子光譜術即是測量電子的動能(E_{k})的技術。當分子被游離的瞬間，離子和電子(被稱為光電子)同時產生，離子和電子以類似"爆炸"式飛離開時，由動量守恆的定理得知m_{1}v_{1} = m_{2}v_{2}，假設1,2分別代表離子和光電子，已知離子的質量遠大於光電子(m_{1}>>m_{2})，因此v_{1}<<v_{2}, 並且 E_{k}^{ion }= m_{1}(v_{1})^{2} << m_{2}(v_{2})^{2 }= E_{k}，光電子將帶著動能E_{k}快速地飛離"爆炸"現場(游離反應中心)。一般說來，離子態分子的動能(E_{k}^{ion})很小可被忽略， 實驗過程中E_{hv}光子的能量(E_{hv})是已知的，由測量的光電子光譜可得知分子的游離能和離子的內能。由於轉動能量比振動能量小很多，離子的內能常被解釋成離子的振動能量. 光電子光譜術的解析度一般可達~0.01 eV = 10 meV (80 cm^{1})。 

Photoinduced Rydberg Ionization (PIRI)
spectroscopy 光誘導雷得堡游離光譜術，詳細敘述請參看另一網頁[webpage PIRI]。 

PPP, PariserParrPople method, a semiemperical procedure  
Predissociation Predissociation is a dissociation that occurs in a transition before the transition limit is attained. It is detected by blurring of the absorption lines followed by the resumption of sharp lines at higher frequency before the onset of the true dissociation limit. 

Progression A progression is a series of lines that arise from transitions from the same vibrational level of one of the states (the ground electronic state for absorption) to successive vibrational levels of the other state. E.g. v” = 0, v” = 0, 1,2, … 

Pulsed field ionization (PFI) 脈衝場游離是個很重要的技術，尤其應用在光電子光譜和臨界游離光譜術方面。當分子吸收單個真空紫外光或多個紫外光，可能處於高雷得堡態，若外加一脈衝電場即可將它游離, 此游離過程即所謂的脈衝場游離。 

Quantum
defect The quantum defect arises from the effect of the other electrons in the atoms on the electron of interest. It decreases as the principal quantum number of the electron increases, for as n increases the electron is progressively further away from the nucleus and its surrounding core electrons increasingly resemble a single point charge. The quantum defect is a quide to the extent of penetration, but it has little other theoretical significant importance. 

Raman
process The Raman process is the inelastic scattering of a photon by a molecule. In Raman scattering the incident photon may lose energy to the molecule by exciting its rotation or vibration, in which case it emerges from the collision with a lower frequency. Alternatively, the photon may acquire energy from the molecule if a mode is already excited and hence energy with a higher frequency. Since molecular rotation and vibration are quantized, the energy transfer can occur only in packets, and so the scattered light contains frequency components that are shifted from the incident frequency by discrete amounts. The frequency composition of the scattered radiation is the Raman spectrum of the molecule. 

Raman
Spectroscopy Raman scattering of light by molecules may be used to provide information on a sample's chemical composition and molecular structure. 

Reduced mass, μ = (m_{a}•m_{b}) / (m_{a}+m_{b})  
Reduced mass, μ = (m_{a}•m_{b}) / (m_{a}+m_{b})  
RennerTeller
effect (splitting, coupling, or interaction) The interaction between the rovibrational and electron angular momenta is referred to as RennerTeller interaction, which results in a splitting in the energy levels. One of the simplest cases is that an energy splitting is produced by the interaction of the electronic and vibrational angular momenta. Therefore vibronic coupling (interaction) can lead to a RennerTeller splitting. 

Resonanceenhanced multiphoton
ionization (REMPI) spectroscopy 

Rotational constant, B_{e} = h/(8π^{2}I_{e}) [Note that I_{e} =μR_{e}^{2}] (for diatomics) 

RRK theory, RiceRamspergerKessel theory  
RRK theory, RiceRamspergerKesselMarcus theory  
Schrödinger equation 

Semiemperical
calculation Semiemperical calculation uses a Hamiltonian simpler than the correct one, and takes some of the integrals as parameters whose values are determined using experimental data. 半經驗式計算法 

Spectrosocpy Spectroscopy is a technique that uses the interaction of energy with a sample to perform an analysis. There are several instruments that are used to perform a spectroscopic analysis. In simplest terms, spectroscopy requires an energy source (commonly a laser, but this could be an ion source or radiation source) and a device for measuring the change in the energy source after it has interacted with the sample (often a spectrophotometer or interferometer). 

Spectrum The data that is obtained from spectroscopy is called a spectrum. A spectrum is a plot of the intensity of energy detected versus the wavelength (or mass or momentum or frequency, etc.) of the energy. A spectrum can be used to obtain information about atomic and molecular energy levels, molecular geometries, chemical bonds, interactions of molecules, and related processes. Often, spectra are used to identify the components of a sample (qualitative analysis). Spectra may also be used to measure the amount of material in a sample (quantitative analysis). 

Stark
effect In 1913, German Physicist Johannes Stark observed the Stark effect which is the modification of the energy levels of atomic and molecular spectra by the application of an electric field. 

Stimulated RamanUV double resonance
spectroscopy 光誘導拉曼紫外光雙共振光譜術，此技術的原理與紅外及紫外光雙共振光譜術非常相似，也是結合REMPI(通常應用紫外雷射光技術，方法是以雷射光來使系統(分子，複合物或團簇)經由拉曼躍遷的機制被昇至某一振動能階(系統則處於電子基態振動激發態)，造成REMPI光譜訊號減弱或增強，若連續改變光誘導的雷射(稱為pump laser)波長，便可以記錄拉曼光譜（Raman spectroscopy），獲得系統在振動模式及能量。 這種技術有兩種不同機制，第一種是記錄系統在電子基態時因為拉曼躍遷而引起所減弱的離子訊號，稱為Ionizationloss stimulated Raman spectroscopy；另一種則是連續改變光誘導雷射波長，記錄因為拉曼吸收而造成的能階躍遷而增強的離子訊號，稱之為：Ionizationgain stimulated Raman spectroscopy。 

Twocolor resonant twophoton
ionization (2CR2PI) spectroscopy 

Timeresolved spectroscopy 

Threshold
photoelectron (TPE) spectroscopy 

Ultraviolet photoelectron spectroscopy 

Ultraviolet
spectroscopy 

Uncertainty
principle 

UVIR double resonance spectroscopy 

Vibrational frequency, ν = (1/2π) •(k/μ)^{1/2} (for diatomics) 

Vibronic
transition 

Visible
spectroscopy 

Wavefunction 

Wavepacket 

Xray
Spectroscopy This technique involves excitation of inner electrons of atoms, which may be seen as xray absorption. An xray fluorescence emission spectrum may be produced when an electron falls from a higher energy state into the vacancy created by the absorbed energy. 

ZDO, Zero differential overlap, a semiemperical approximation 

Zeeman
effect 

Zero kinetic energy
(ZEKE) spectroscopy [webpage ZEKE] 

Zero
point energy 
背景音樂: [Eldelweiss小白花]
上次網頁修改日期:
2006/05/02