scholarly journals Internal Energy Distribution in MgO(a3Π) Formed From Mg(3P) + O2 and N2O : A Case of Population Inversion

1986 ◽  
Vol 6 (1) ◽  
pp. 15-35 ◽  
Author(s):  
Bernard Bourguignon ◽  
Joelle Rostas ◽  
Guy Taieb ◽  
Mohammed-Ali Gargoura ◽  
June McCombie
Keyword(s):  
Ground State ◽  
Fluorescence Spectra ◽  
Population Distribution ◽  
Internal State ◽  
Boltzmann Distribution ◽  
Rotational Excitation ◽  
State Distribution ◽  
Population Distributions ◽  
Vibrational Population ◽  
Π State

The internal state distribution of MgO(a3Π) formed from Mg(3P) + O2 and N2O reactions was determined from a reanalysis of the laser induced fluorescence spectra of the d3Δ - a3Π system previously published by Dagdigian. The MgO(a3Π) state formed in the reaction with O2 has a quasi-Boltzmann distribution. In the N2O reaction the rotational excitation is much greater and the vibrational population distribution is inverted with a maximum at v = 2 - 3. The a3Π rovibrational population distributions are compared with those of the X1∑+ ground state. The dynamics of these reactions are discussed on the basis of earlier ab-initio calculations and experimental data.

The vibrational population distribution of H 2 +. formed from a series of different precursor molecules

1984 ◽  
Vol 395 (1808) ◽  
pp. 111-125 ◽  
Keyword(s):  
Population Distribution ◽  
Kinetic Energy Release ◽  
Hydrogen Gas ◽  
Small Deviations ◽  
Population Distributions ◽  
Vibrational Levels ◽  
Product Ions ◽  
Vibrational Population ◽  
Precursor Molecules ◽  
Kinetic Energy Release Distribution

The collision induced spectra of H 2 +. → H + have been measured by translational spectroscopy, where the hydrogen molecular ion was formed from a series of hydrogen-containing precursors. Differences in the shapes of the collision-induced spectra were observed, which reflect upon the initial vibrational distributions in which H 2 +. was formed. These distri­butions were calculated, for each precursor, by associating to each vibrational level an individual kinetic energy release distribution, from which the experimentally observed spectra were regenerated by a computer simulation. Each calculated distribution was normalized to a previously published vibronic distribution obtained from a photo­dissociation study of H 2 +. . The vibrational population distributions of H 2 +. product ions, for each precursor, show small deviations, for v ≼ 12, from that obtained when hydrogen gas was the precursor, and differences of between a factor 0.8 to 3 for higher vibrational levels.

scholarly journals Energy Partitioning in Molecular Photodissociation: Methyl Nitrite Photolysis

1983 ◽  
Vol 3 (1-6) ◽  
pp. 97-106 ◽  
Author(s):  
F. Lahmani ◽  
C. Lardeux ◽  
D. Solgadi
Keyword(s):  
Excited States ◽  
Internal State ◽  
Energy Partitioning ◽  
Rotational Excitation ◽  
State Distribution ◽  
Methyl Nitrite ◽  
Two Photon ◽  
Electronically Excited ◽  
Molecular Photodissociation ◽  
High Degree

The photodissociation of methyl nitrite CH3ONO in three different electronically excited states has been studied by determining the internal state distribution of one of the photofragments. The fluorescence of NO A Σ2+ produced for excitation of CH3ONO between 1200 and 1650 Å and of CH3O 2 A1 produced at 1930 Å has been investigated. The vibrational distribution in both species can be explained by statistical considerations. The rotational excitation of NO A Σ2+ is of Boltzmann type. For CH3ONO excited in the first nπ* excited state at 3550 Å the NO X fragment has been probed by a two photon laser excited fluorescence technique. The nascent NO X υ″ = 0, 1, 2, 3 exhibit a population inversion and a high degree of rotational excitation.

Vibrational population distribution of ground state BaO formed by the reaction Ba + O2

1976 ◽  
Vol 39 (3) ◽  
pp. 454-456 ◽  
Author(s):  
Michael A. Revelli ◽  
Brian G. Wicke ◽  
David O. Harris
Keyword(s):  
Ground State ◽  
Population Distribution ◽  
Vibrational Population

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

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.

scholarly journals Research on Human Travel Correlation for Urban Transport Planning Based on Multisource Data

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 195
Author(s):  
Hua Chen ◽  
Ming Cai ◽  
Chen Xiong
Keyword(s):  
Travel Demand ◽  
Population Distribution ◽  
Human Mobility ◽  
Urban Transport ◽  
License Plate ◽  
Traffic Patterns ◽  
Trajectory Data ◽  
Transport Planning ◽  
Population Distributions ◽  
Single Dataset

With the rapid development of positioning techniques, a large amount of human travel trajectory data is collected. These datasets have become an effective data resource for obtaining urban traffic patterns. However, many traffic analyses are only based on a single dataset. It is difficult to determine whether a single-dataset-based result can meet the requirement of urban transport planning. In response to this problem, we attempted to obtain traffic patterns and population distributions from the perspective of multisource traffic data using license plate recognition (LPR) data and cellular signaling (CS) data. Based on the two kinds of datasets, identification methods of residents’ travel stay point are proposed. For LPR data, it was identified based on different vehicle speed thresholds at different times. For CS data, a spatiotemporal clustering algorithm based on time allocation was proposed to recognize it. We then used the correlation coefficient r and the significance test p-values to analyze the correlations between the CS and LPR data in terms of the population distribution and traffic patterns. We studied two real-world datasets from five working days of human mobility data and found that they were significantly correlated for the stay and move population distributions. Then, the analysis scale was refined to hour level. We also found that they still maintain a significant correlation. Finally, the origin–destination (OD) matrices between traffic analysis zones (TAZs) were obtained. Except for a few TAZs with poor correlations due to the fewer LPR records, the correlations of the other TAZs remained high. It showed that the population distribution and traffic patterns computed by the two datasets were fairly similar. Our research provides a method to improve the analysis of complex travel patterns and behaviors and provides opportunities for travel demand modeling and urban transport planning. The findings can also help decision-makers understand urban human mobility and can serve as a guide for urban management and transport planning.

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