Resonance-enhanced multiphoton ionization spectroscopy of CH3 and CD3. Two-photon absorption selection rules and rotational line strengths of the ν3- and ν4-active vibronic transitions

2004 ◽  
Vol 224 (2) ◽  
pp. 145-150
Author(s):  
Kuo-mei Chen
Keyword(s):  
Multiphoton Ionization ◽  
Photon Absorption ◽  
Rotational Line ◽  
Selection Rules ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Vibronic Transitions ◽  
Multiphoton Ionization Spectroscopy ◽  
Line Strengths

scholarly journals Multiphoton Bleaching of Red Fluorescent Proteins and the Ways to Reduce It

2022 ◽  
Vol 23 (2) ◽  
pp. 770
Author(s):  
Mikhail Drobizhev ◽  
Rosana S. Molina ◽  
Jacob Franklin
Keyword(s):  
Chemical Structure ◽  
Fluorescent Proteins ◽  
Multiphoton Ionization ◽  
Excitation Power ◽  
Photon Absorption ◽  
Green Fluorescent Proteins ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Red Fluorescent Proteins ◽  
Green Fluorescent

Red fluorescent proteins and biosensors built upon them are potentially beneficial for two-photon laser microscopy (TPLM) because they can image deeper layers of tissue, compared to green fluorescent proteins. However, some publications report on their very fast photobleaching, especially upon excitation at 750–800 nm. Here we study the multiphoton bleaching properties of mCherry, mPlum, tdTomato, and jREX-GECO1, measuring power dependences of photobleaching rates K at different excitation wavelengths across the whole two-photon absorption spectrum. Although all these proteins contain the chromophore with the same chemical structure, the mechanisms of their multiphoton bleaching are different. The number of photons required to initiate a photochemical reaction varies, depending on wavelength and power, from 2 (all four proteins) to 3 (jREX-GECO1) to 4 (mCherry, mPlum, tdTomato), and even up to 8 (tdTomato). We found that at sufficiently low excitation power P, the rate K often follows a quadratic power dependence, that turns into higher order dependence (K~Pα with α > 2) when the power surpasses a particular threshold P*. An optimum intensity for TPLM is close to the P*, because it provides the highest signal-to-background ratio and any further reduction of laser intensity would not improve the fluorescence/bleaching rate ratio. Additionally, one should avoid using wavelengths shorter than a particular threshold to avoid fast bleaching due to multiphoton ionization.

Anisotropic selection rules of two-photon absorption of GaAs quantum wires

1993 ◽  
Vol 13 (1) ◽  
pp. 71-74 ◽  
Author(s):  
R. Cingolani ◽  
M. Lepore ◽  
R. Tommasi ◽  
I.M. Catalano ◽  
H. Lage ◽  
...  
Keyword(s):  
Quantum Wires ◽  
Photon Absorption ◽  
Selection Rules ◽  
Two Photon Absorption ◽  
Two Photon

Detection of Atmospheric Pollutant NO With the Method of Resonant-Enhanced Multiphoton Ionization

2012 ◽  
Vol 209-211 ◽  
pp. 1596-1599
Author(s):  
Gui Yin Zhang ◽  
Yi Dong Jin ◽  
Hai Ming Zheng
Keyword(s):  
Decay Curve ◽  
Resonant State ◽  
Multiphoton Ionization ◽  
Photon Absorption ◽  
Ionization Cross ◽  
Atmospheric Pollutant ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photon Ionization ◽  
Key Substances

NO is one of the key substances of air pollution. This paper presents the use of the technique of resonant enhanced multi-photon ionization (REMPI) for NO ambient detection. NO is ionized by absorbing four photons and via A2Σ intermediate resonant state when use 452.4nm laser as radiation source. A physical model concerning the ionization process is presented. It is shown that the ion signal depends on laser character and the dynamic parameters of NO. Two-photon absorption and ionization cross section about the resonant state are obtained from the ion decay curve and the model. The detection limit of this work, which can reach 1.4 ppm, is determined by measuring the variation of the ion signal with the concentration of NO.

Selection rules for direct creation of biexcitons by giant two-photon absorption

1975 ◽  
Vol 17 (2) ◽  
pp. 189-192 ◽  
Author(s):  
E. Doni ◽  
R. Girlanda ◽  
G. Pastori Parravicini
Keyword(s):  
Photon Absorption ◽  
Selection Rules ◽  
Two Photon Absorption ◽  
Two Photon

Three- and two-photon absorption spectroscopy: REMPI of HCl and HBr

2001 ◽  
Vol 79 (2-3) ◽  
pp. 197-210 ◽  
Author(s):  
Á. Kvaran ◽  
H Wang ◽  
B G Waage
Keyword(s):  
Absorption Line ◽  
Line Strength ◽  
Multiphoton Ionization ◽  
Photon Absorption ◽  
Excitation Process ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Population Distributions ◽  
Photon Excitation ◽  
First Time

Approximation expressions for absorption line strengths due to Ω' = 0,1,2,3 ¬ Ω" = 0 (Σ, Π, Δ, and Φ ¬ Σ) transitions for three-, two-, and one-photon absorptions are summarized. Those for three- and two-photon absorptions are used to analyse room temperature (3+1) and (2+1) REMPI (resonance enhanced multiphoton ionization) spectra due to transitions to Rydberg states in HCl and HBr to give spectroscopic parameters. A mechanism of the three-photon excitation process for the (E1 Σ+) ¬ X(1Σ+), (0,0) transition in HCl is proposed. A Rydberg state, not observed in single- or two-photon absorption, with a band origin at 80 167 cm-1 was identified in (3+1) REMPI of HBr and analysed for the first time. It was assigned to the l(3(Φ(Ω' = 3)) ((σ2π3)5dδ) state, (0,0) band. Use of the three-photon absorption line strength expressions for deriving rotational population distributions in ground-state HBr is demonstrated. PACS Nos.: 03.40Kf, 42.65Tg, 42.81Dp

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