Excitation spectrum of the near-ultraviolet bands of CS2

1980 ◽  
Vol 58 (5) ◽  
pp. 454-457 ◽  
Author(s):  
R. Vasudev ◽  
J. C. D. Brand
Keyword(s):  
Excitation Spectrum ◽  
Spontaneous Emission ◽  
Ground State ◽  
Band System ◽  
Tunable Laser ◽  
Laser Source ◽  
Intersystem Crossing ◽  
Near Ultraviolet ◽  
Resonance Emission ◽  
Singlet Band

An excitation spectrum of the triplet–singlet band system of CS2 vapor has been measured in the range 365–378 nm using a tunable laser source. Overall intensity is relatively insensitive to pressure in the range (150 m Torr – 340 Torr) tested in these observations. The results indicate that collisions with ground state molecules of CS2 are efficient in promoting intersystem crossing to the ground state, and that the spontaneous emission observed is primarily resonance emission from the state populated by the radiation.

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

Spin-Forbidden Excitation Enables Infrared Photoredox Catalysis

2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Intersystem Crossing ◽  
Photoredox Catalysis ◽  
Infrared Irradiation ◽  
Triplet Excitation ◽  
New Family ◽  
Ir Light

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

The Dielectric Discharge as an Efficient Generator of Active Nitrogen for Chemiluminescence and Analysis

1983 ◽  
Vol 37 (6) ◽  
pp. 545-552 ◽  
Author(s):  
John Kishman ◽  
Eric Barish ◽  
Ralph Allen
Keyword(s):  
Gas Phase ◽  
Ground State ◽  
Band System ◽  
Electrothermal Atomization ◽  
Characteristic Radiation ◽  
Gaseous Species ◽  
Vibrationally Excited ◽  
Active Nitrogen ◽  
Excited Species ◽  
Intense Emission

A predominantly blue “active nitrogen” afterglow was generated in pure flowing nitrogen or in air by using a dielectric discharge at pressures from 1 to 20 Torr. The afterglow contains triplet state molecules and vibrationally excited ground state molecules. These species are produced directly by electron impact without the formation and recombination of nitrogen atoms. The most intense emission is the N2 second positive band system. The N2 first positive and N2+ first negative systems are also observed. The spectral and electrical properties of this discharge are discussed in order to establish guidelines for the analytical use of the afterglow for chemiluminescence reactions. The metastatic nitrogen efficiently transfers its energy to atomic and molecular species which are introduced into the gas phase and these excited species emit characteristic radiation. The effects of electrothermal atomization of Zn and the introduction of gaseous species (e.g., NO) on the afterglow are described.

scholarly journals LATTICE QCD AND STRING THEORY

2006 ◽  
Vol 21 (04) ◽  
pp. 699-706 ◽  
Author(s):  
JULIUS KUTI
Keyword(s):  
String Theory ◽  
Lattice Qcd ◽  
Excitation Spectrum ◽  
Ground State ◽  
Gauge Theories ◽  
Casimir Energy ◽  
Closed String ◽  
Compact Dimension ◽  
Electric Flux ◽  
String Formation

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension is also discussed.

THE ABSORPTION SPECTRUM OF CF2

1967 ◽  
Vol 45 (7) ◽  
pp. 2355-2374 ◽  
Author(s):  
C. Weldon Mathews
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Vibrational Structure ◽  
Rotational Structure ◽  
Transition Moment ◽  
High Dispersion ◽  
Parallel Type

The absorption spectrum of CF2 in the 2 500 Å region has been photographed at high dispersion, and the rotational structure of a number of bands has been analyzed. The analysis of the well-resolved subbands establishes that these are perpendicular- rather than parallel-type bands, as previously assigned. Further analysis shows that the upper and lower electronic states are of 1B1 and 1A1symmetries respectively, corresponding to a transition moment that is perpendicular to the plane of the molecule. In the upper electronic state, r0(CF) = 1.32 Å and [Formula: see text], while in the ground state, r0(CF) = 1.300 Å and [Formula: see text]. An investigation of the vibrational structure of the band system has shown that the vibrational numbering in ν2′ must be increased by one unit from earlier assignments, thus placing the 000–000 band near 2 687 Å (37 220 cm−1). A search between 1 300 and 8 500 Å showed two new band systems near 1 350 and 1 500 Å which have been assigned tentatively to the CF2 molecule.

SENSITIVITY MEASUREMENT OF FIBRE BRAGG GRATING SENSOR

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Suzairi Daud ◽  
Muhammad Safwan Abd Aziz ◽  
Kashif Tufail Chaudhary ◽  
Mahdi Bahadoran ◽  
Jalil Ali
Keyword(s):  
Tunable Laser ◽  
Sensor System ◽  
Laser Source ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Fibre Bragg Grating ◽  
Sensor Head ◽  
Fibre Bragg Grating Sensor ◽  
Pass Through ◽  
Bragg Grating Sensor

A practical pass-through type fibre Bragg grating (FBG) temperature sensor system have been designed, developed, simulated, and experimentally investigated. The performance of FBG was evaluated in harsh environments exposed under direct sunlight, rain, and wind. The sensor system designed directly focused with convex and hand lens. The temperature of FBG’s sensor head been measured. The broadband laser source was launched into the system using tunable laser source (TLS) and both transmission and reflection spectra of FBG sensor were measured by optical spectrum analyzer (OSA). Results shows that the Bragg wavelength shift,  increased proportionally with the temperature changes. The sensitivity of FBG were recorded at 0.0100 and 0.0132 nm °C-1 for the systems where convex and hand lens applied to the FBG’s sensor head respectively, while the sensitivity of 0.0118 nm °C-1 measured for the system without any focusing element applied.

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