scispace - formally typeset
Search or ask a question
Topic

Photoexcitation

About: Photoexcitation is a research topic. Over the lifetime, 5874 publications have been published within this topic receiving 134733 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors used dispersed fluorescence scans of the A-X(4,v") and D-X (0,v) progressions of nitric oxide, after two-photon excitation, to determine the electronic transition moments of these band systems.
Abstract: Dispersed fluorescence scans of the A–X(4,v″) and D–X(0,v″) progressions of nitric oxide, after two-photon excitation, are used to determine the electronic transition moments of these band systems. The measured collision free lifetimes of 206±7 ns for A 2Σ+, v′=0, and 18±1 ns for D 2Σ+, v′=0 are used to place transition probabilities on an absolute basis. The branching ratio for D→X is 3.0±0.3 times that for D→A and more than 30 times that for D→C. The ratio of two-photon absorption cross sections for D–X(0,0)/A–X(4,0) is 6±2 and the photoionization probability from D, v′=0 is larger than from A, v′=4 at 375 nm. Also, the two-photon excitation of A–X(4,0) has an unusual intensity distribution, probably due either to interference between intermediate states in the excitation or to anomalies in the photoionization step.

107 citations

Journal ArticleDOI
TL;DR: In this article, a semi-empirical diatomics-in-molecules (DIM) excited state electronic structure technique is used to compute the ion pair states of the I2-rare gas crystal system and use these states together with a model of the configurational dependence of the electronic dipole operator matrix elements to calculate the time resolved probe absorption signals in these pump-probe experiments using a simple golden rule result.
Abstract: Recent experimental studies of both A and B state photoexcitation of I2 and the ensuing many-body dynamics in rare gas matrices by Apkarian and co-workers are simulated using the methods we presented in an earlier work combining nonadiabatic molecular dynamics with semiempirical diatomics-in-molecules (DIM) excited state electronic structure techniques. We extend our DIM methods to compute the ion pair states of the I2-rare gas crystal system and use these states together with a model of the configurational dependence of the electronic dipole operator matrix elements to calculate the time resolved probe absorption signals in these pump - probe experiments using a simple golden rule result. Our computed signals are in remarkable agreement with experiments and we use our calculations to provide a detailed microscopic analysis of the channels to predissociation and recombination underlying these experiments.

106 citations

Journal ArticleDOI
TL;DR: Analyzing the changes occurring at the semiconductor surface upon photoexcitation under a controlled oxygen atmosphere in an X-ray photoelectron spectroscopy (XPS) chamber can rationalize the rich variety of photophysical phenomena observed and provide a plausible explanation for light-induced ion migration.
Abstract: Herein we present a combined study of the evolution of both the photoluminescence (PL) and the surface chemical structure of organic metal halide perovskites as the environmental oxygen pressure rises from ultrahigh vacuum up to a few thousandths of an atmosphere. Analyzing the changes occurring at the semiconductor surface upon photoexcitation under a controlled oxygen atmosphere in an X-ray photoelectron spectroscopy (XPS) chamber, we can rationalize the rich variety of photophysical phenomena observed and provide a plausible explanation for light-induced ion migration, one of the most conspicuous and debated concomitant effects detected during photoexcitation. We find direct evidence of the formation of a superficial layer of negatively charged oxygen species capable of repelling the halide anions away from the surface and toward the bulk. The reported PL transient dynamics, the partial recovery of the initial state when photoexcitation stops, and the eventual degradation after intense exposure times c...

106 citations

Journal ArticleDOI
T. Aberg1
TL;DR: In this paper, a relative cross section for simultaneous excitation and ionization of the helium atom is derived from the sudden approximation, which is shown to agree with that obtained from the velocity form of the cross section in the Coulomb approximation.
Abstract: A relative cross section for simultaneous excitation and ionization of the helium atom is derived from the sudden approximation. It is shown to agree with that obtained from the velocity form of the cross section in the Coulomb approximation. It is connected to the asymptotic cross section of Kabir and Salpeter through the cusp condition at the nucleus. An analysis of the influence of ground-state correlations on the asymptotic double-excitation cross section is carried out.

105 citations

Journal ArticleDOI
TL;DR: In this article, the photophysical properties of the supramolecular composites of two π-electron semiconductors; conjugated polymers as electron donors and Buckminsterfullerene as electron acceptor are discussed.

105 citations


Network Information
Related Topics (5)
Raman spectroscopy
122.6K papers, 2.8M citations
92% related
Band gap
86.8K papers, 2.2M citations
91% related
Amorphous solid
117K papers, 2.2M citations
87% related
Graphene
144.5K papers, 4.9M citations
86% related
Thin film
275.5K papers, 4.5M citations
86% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023249
2022529
2021221
2020204
2019183
2018256