scholarly journals Detection limits of organic compounds achievable with intense, short-pulse lasers

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 4270-4276 ◽  
Author(s):  
Jordan Miles ◽  
Simone De Camillis ◽  
Grace Alexander ◽  
Kathryn Hamilton ◽  
Thomas J. Kelly ◽  
...  

Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization.

2013 ◽  
Vol 20 (2) ◽  
pp. 183-190 ◽  
Author(s):  
A. Barna ◽  
I. B. Földes ◽  
Z. Gingl ◽  
R. Mingesz

Abstract In experiments with short-pulse lasers the measurement control of the energy of the laser pulse is of crucial importance. Generally it is difficult to measure the amplitude of the pulses of short-pulse lasers using electronic devices, their response time being longer than the duration of the laser pulses. The electric response of the detector is still too fast to be directly digitized therefore a peak-hold unit can be used to allow data processing for the computer. In this paper we present a device which measures the energy of UV short (fs) pulses shot-byshot, digitizes and sends the data to the PC across an USB interface. The circuit is based on an analog peak detect and hold unit and the use of fiber optical coupling between the PC and the device provides a significant improvement to eliminate potential ground loops and to reduce conductive and radiated noise as well. The full development is open source and has been made available to download from our web page (http://www.noise.inf.u-szeged.hu/Instruments/PeakHold/).


2000 ◽  
Vol 65 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Pavel Hradil ◽  
Jiří Votinský ◽  
Karel Komárek ◽  
Vítězslav Zima ◽  
Jaroslava Kalousová ◽  
...  

Gas chromatographic measurement of specific retention volumes of vapours of selected groups of organic compounds has been used to determine differential molar enthalpy of adsorption of their molecules on the surface of layered vanadyl phosphate substituted with ferric ions having the composition of [Fe(H2O)]0.20(VO)0.80PO4. Various types of bonds of the molecules to the surface of the layered adsorbent including their probable orientation with respect to the layers have been discussed. It was observed a dependence of the specific peak elution volume and shape of chromatographic peak on the sample size in the cases of those compounds whose molecules are chemically bound to the adsorbent surface. A connection is pointed out between the adsorption strength of the organic molecules on the layered adsorbent and the tendency of the system to undergo intercalation reaction.


Author(s):  
E. Brambrink ◽  
S. Baton ◽  
M. Koenig ◽  
R. Yurchak ◽  
N. Bidaut ◽  
...  

We have developed a new radiography setup with a short-pulse laser-driven x-ray source. Using a radiography axis perpendicular to both long- and short-pulse lasers allowed optimizing the incident angle of the short-pulse laser on the x-ray source target. The setup has been tested with various x-ray source target materials and different laser wavelengths. Signal to noise ratios are presented as well as achieved spatial resolutions. The high quality of our technique is illustrated on a plasma flow radiograph obtained during a laboratory astrophysics experiment on POLARs.


2011 ◽  
Vol 18 (10) ◽  
pp. 103103 ◽  
Author(s):  
Alexander Andreev ◽  
Naveen Kumar ◽  
Konstantin Platonov ◽  
Alexander Pukhov

2001 ◽  
Vol 19 (3) ◽  
pp. 237-244 ◽  
Author(s):  
Nikolai V. Nikolenko

The energies of unoccupied and occupied orbitals were used as the correlation parameters between the electronic and adsorptive properties of organic molecules. A model describing the chemisorption of organic compounds on CaCO3 involving two types of interaction, i.e. two-electron, donor–acceptor interaction HOMO(adsorbent) → LUMO(adsorbate) and four-electron, three-orbital interaction HOMO(adsorbent) → {LUMO(adsorbate) + HOMO(adsorbate)}, was proposed. It was concluded that strengthening of the bond involved in chemisorption occurred if the energies of the occupied orbitals associated with the adsorbate and adsorbent were concurrent.


Sign in / Sign up

Export Citation Format

Share Document