Dynamics of the two‐photon photodissociation of NO2: A molecular beam multiphoton ionization study of NO photofragment internal energy distributions

1982 ◽  
Vol 77 (12) ◽  
pp. 5994-6004 ◽  
Author(s):  
Richard J. S. Morrison ◽  
Edward R. Grant
Keyword(s):  
Internal Energy ◽  
Molecular Beam ◽  
Multiphoton Ionization ◽  
Energy Distributions ◽  
Two Photon

Dynamics and yields for CHBrCl2photodissociation from 215–265 nm

2016 ◽  
Vol 18 (48) ◽  
pp. 32999-33008 ◽  
Author(s):  
Wyatt G. Merrill ◽  
F. Fleming Crim ◽  
Amanda S. Case
Keyword(s):  
Mass Spectrometry ◽  
Internal Energy ◽  
Multiphoton Ionization ◽  
Energy Partitioning ◽  
Quantum Yields ◽  
Velocity Map Imaging ◽  
Spin Orbit ◽  
Energy Distributions ◽  
Flight Mass Spectrometry ◽  
Relative Quantum

We characterize the energy partitioning and spin–orbit yields for CHBrCl2photodissociation. Resonance enhanced multiphoton ionization selectively detects the Br and Br* product channels. Time of flight mass spectrometry and velocity-map imaging permit measurement of relative quantum yields, as well as kinetic and internal energy distributions. We further interpret the energy partitioning through use of impulsive models.

scholarly journals Laser-assisted two-color two-photon double ionization of helium atoms

2021 ◽  
Author(s):  
Zhizhen Zhu ◽  
Kai Liu ◽  
Xiaofan Zhang ◽  
Ye Li ◽  
Feng Wang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Laser Field ◽  
Double Ionization ◽  
Destructive Interference ◽  
Energy Distributions ◽  
Laser Photon ◽  
One Dimensional ◽  
Helium Atoms ◽  
Two Photon ◽  
Kinetic Energy Distributions

Abstract Correlated momentum and kinetic energy distributions of two photoelectrons in laser-assisted two-color two-photon double ionization of helium are investigated by numerically solving a one-plus-one dimensional time-dependent Schr\"{o}dinger equation (TDSE). We find that the weak assisting laser field can act as an energy transferring field, resulting in burst of double ionization. More importantly, the participation of the laser photon into the double ionization reshapes the correlation patterns in the momentum and kinetic energy distributions. The laser photon can be absorbed by any one of the two electrons, providing two channels that induces destructive interference in the correlated momentum and kinetic energy distributions, which is never found in previous work.

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.

Internal energy distributions from nitrogen dioxide fluorescence. 1. Cumulative sum method

1993 ◽  
Vol 97 (39) ◽  
pp. 9890-9903 ◽  
Author(s):  
H. S. Johnston ◽  
C. E. Miller ◽  
B. Y. Oh ◽  
K. O. Patten ◽  
W. N. Sisk
Keyword(s):  
Nitrogen Dioxide ◽  
Internal Energy ◽  
Cumulative Sum ◽  
Energy Distributions ◽  
Cumulative Sum Method
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