Papers by Stephen H Ashworth
African Journal of Chemical Education, Jul 1, 2018
The Kitchen Chemistry Science Show uses readily available materials and unsophisticated equipment... more The Kitchen Chemistry Science Show uses readily available materials and unsophisticated equipment. The development of the show is outlined and each of the demonstrations is described in detail. For each demonstration there is an explanation of the demonstration and, where appropriate, a suggestion for an extension to a whole class activity. Indications of safety precautions are also discussed. Further development of the Kitchen Chemistry Outreach Project is then outlined with a description of future plans.
Chemical Physics Letters, Apr 1, 2006
We report dispersed fluorescence (DF) spectra of the isobutoxy and 2-methyl-1-butoxy radicals pro... more We report dispersed fluorescence (DF) spectra of the isobutoxy and 2-methyl-1-butoxy radicals produced by photolysis of corresponding nitrites in supersonic jet expansion. Different vibrational structures have been observed in the DF spectra when different vibronic bands in the laser-induced fluorescence (LIF) spectra of each radical were pumped, which suggests that those vibronic bands be assigned to different conformers. Spectra simulated using calculated vibrational frequencies and Franck−Condon factors well reproduce the experimentally observed ones and support the assignment of the vibronic bands in the LIF spectra to the two lowest-energy conformers of each radical. DF spectra obtained by pumping the B̃← X̃origin bands of the LIF spectra are dominated by CO stretch progressions because of the large difference in CO bond length between the ground (X) and the second excited (B) electronic states. Furthermore, with non-CO stretch bands pumped, the DF spectra are dominated by progressions of combination bands of the CO stretch and the pumped modes as a result of Duschinsky mixing. A−X̃separation of both conformers of the isobutoxy radical has also been determined in the experiment.
Contemporary Physics, Jan 2, 2022
Journal of Chemical Physics, Feb 20, 2003
Journal of Raman Spectroscopy, Jul 1, 1997
Page 1. JOURNAL OF RAMAN SPECTROSCOPY, VOL. 28, 537»546 (1997) Resonance and Optical Dephasing St... more Page 1. JOURNAL OF RAMAN SPECTROSCOPY, VOL. 28, 537»546 (1997) Resonance and Optical Dephasing Study of Raman Tricarbocyanine Dyes Stephen H. Ashworth1§, Andreas Kummrow2* and Kurt Lenz1 1 Max-Born ...
Laser Chemistry, 1999
Line shape analysis based on resonance Raman spectra of HITCI is used to determine the details of... more Line shape analysis based on resonance Raman spectra of HITCI is used to determine the details of the vibrational part of the line broadening function. Forced Light Scattering with 20 fs pulses from a Ti: sapphire laser measured optical dephasing probing with an Ar laser. The observed response is well described by the line broadening function derived from the fluorescence line shape.
Journal of Physical Chemistry A, Dec 13, 2005
Аннотация. В исследовании поставлена цель: проанализировать понятия «идеал», «идеал воспитания че... more Аннотация. В исследовании поставлена цель: проанализировать понятия «идеал», «идеал воспитания человека», «идеал воспитательного процесса» и на основе данных понятий выявить идеал воспитания человека в трудах педагогов-антропологов ХIХ в. Для достижения цели решаются следующие задачи: проанализировать понятия «идеал» в философском и педагогическом аспектах, на его основе провести сравнительный анализ идеала воспитания человека и идеала воспитательного процесса в трудах педагогов-антропологов данного периода В. Г. Белинского, Н. Г. Чернышевского, Н. А. Добролюбова, Н. И. Пирогова, К. Д. Ушинского в структуре педагогической мысли. Для решения поставленных задач использовались теоретические методы: метод историко-педагогического исследования, анализ историко-педагогического факта; сравнительно-исторический; систематизация полученных результатов. Проведена аналогия с современным идеалом воспитания человека.
Journal of Dental Research, 1999
Contemporary Physics, 2021
The discovery and in part also the further study of exoplanets have gained quite a lot of media a... more The discovery and in part also the further study of exoplanets have gained quite a lot of media attention in the last decade or so. The idea that stars other than our Sun may have planets as well, and that these ‘exoplanets’ may be Earth-like and located in the so-called ‘habitable zone’, possibly capable of supporting life, is centuries old. But proof and scientific study have been provided only fairly recently, with the vast majority of scientific results from the NASA Kepler mission, a space probe in an orbit around the Sun, much similar to Earth’s orbit. Named after German astronomer Johannes Kepler, it consists mainly of a large space telescope that has been in operation from 2009 to 2018. During that time, it has observed around half amillion stars and found some 2500 exoplanets, some of which have been shown to be Earth-like and in the habitable zones of their stars. Kepler,mainly being a large photometer, has used the slight periodic variation of the amount of light detected from a star (dimming) when a planet passes in front of it to study that planet. The present book The NASA Kepler Mission sets out to give a general account of this undertaking, from a discussion of the mission and its background to the technology of the probe and the methods of study, and to the variety of scientific results. It is part of the ‘AAS IOP Astronomy’ book series where the American Astronomical Society (AAS) have partnered with IOP Publishing ‘to create an exciting new collection of astronomy and astrophysics books to further the AAS mission to enhance and share humanity’s scientific understanding of the universe.’ The title of the book may as well be The NASA Kepler and K2 Missions (which actually is the title of the first chapter after the introduction), since the original Kepler mission encountered technical problems after about four years of operation, and had to be changed in order to make use of the instrument in spite of those problems, hence creating the so-called ‘K2’ mission, which is also covered in the current text. It consists of a thorough discussion of the mission (‘The NASAKepler and K2Missions’) and an account of the most prominent subjects of study (‘Exoplanets’) followed by the additional fields of study ‘Stellar Astrophysics with Kepler and K2’, ‘The Solar System as Observed by K2’ and ‘Extragalactic Studies from the Kepler/K2 Missions’. The text has been edited by Steve B. Howell from the NASA Ames Research Center, a central figure of the mission, and contains contributions by some twenty authors who were all involved in the various aspects of the mission. The text is nicely written in a somewhat personal style, easily accessible yet precise and fully referenced to scientific publications. It is supported by ample colour plots and pictures taken of and by the Kepler telescope. Rather than having each author contribute one chapter to the book, the individual contributions are short and nicely integrated into the main text by use of text boxes, which increases the readability. It is overall very accessible, also owing to the fact that no mathematics or formal scientific training is necessarily required to understand most of the material presented. The book itself is a hardback (ISBN 9780750322942) and well made regarding the paper, the print and the binding. It is also available as an e-book, in a ‘mobi’ version for mobile reading devices, and offers a ‘myprint’ option for those whose institutions have already bought the book electronically, thus making a print copy available at a price of typicallyUSD30. It can be recommended to anyone with a general interest in the engineering and science of space telescopes, or more specifically with the study of exoplanets by space-based photometry. It provides an interesting and informative read about the Kepler mission for interested laypersons to experts.
Review of Scientific Instruments, 1994
Vibronic relaxation processes of large molecules in the condensed phase, which occur on an ultraf... more Vibronic relaxation processes of large molecules in the condensed phase, which occur on an ultrafast time scale, have been the subject of numerous time-resolved experiments in the regime between 100 fs and several picoseconds,1 Recently, high-repetition-rate solid-state lasers have become available for the generation of pulses of less than 30-fs duration,2·3 allowing the investigation of relaxation steps in time intervals of several tens of femtoseconds, i.e., comparable to vibrational periods of the molecules. In this paper we describe a study of the relaxation of high-lying singlet S„ states in organic-dye molecules in two-color pump-probe measurements with an unprecedented time resolution of about 20 fs, providing new insight into femtosecond material excitations and ultrafast internal conversion processes.
Contemporary Physics, 2017
Author Institution: School of Chemistry, University of Bristol; School of Chemical Sciences, Univ... more Author Institution: School of Chemistry, University of Bristol; School of Chemical Sciences, University of East Anglia
PhysChemComm, 1998
Laser Raman spectra have been obtained for crystalline adamantane, diamantane, and natural type I... more Laser Raman spectra have been obtained for crystalline adamantane, diamantane, and natural type II diamond, as well as for a diamond film grown by chemical vapour deposition (CVD). The spectra are presented in JCAMP format to allow on-line interaction with the data by the reader, and 3D structure animations are presented showing the most probable vibrational mode causing each peak in the various spectra. The spectra are compared to those often seen from CVD diamond films, and which contain peaks that have previously been assigned to 'nanophase' diamond. Although there is a superficial correlation between the peak positions for the polymantanes and those seen in CVD diamond, the conclusion is that the nanophase diamond peaks are not an intrinsic vibrational mode of a polymantane, but instead must be a result of some other aspect of the nanophase scale of the films, such as surface modes. Link to Software requirements
Education in chemistry, 2015
Molecular Physics, 2012
Fourier transform spectra of collisionally induced fluorescence following isotopically selective ... more Fourier transform spectra of collisionally induced fluorescence following isotopically selective laser excitation of NiH at ∼550 nm have located an excited Ω = 1/2 state of NiH lying 17900 cm above the electronic ground state. This is identified as v = 0 of a Π1/2 state originating from an Ni 3d4sF configuration. Emission from this Ω′ = 1/2 state occurs predominantly to v″ = 0 and 1 of the Σ
A description of the history and development of the first Kitchen Chemistry science show, togethe... more A description of the history and development of the first Kitchen Chemistry science show, together with descriptions of most of the demonstrations.
The ultrafast dynamics of the dye molecule IR125 dissolved in ethylene glycol was studied. The sa... more The ultrafast dynamics of the dye molecule IR125 dissolved in ethylene glycol was studied. The sample was excited to high lying electronic states with frequency doubled Ti:sapphire radiation (30 fs duration; center wavelength 425 nm) and then probed with the fundamental (20 fs duration; centered at 850 nm) which overlapped with both the S-0-S-1 absorption and fluorescence bands. Three components were observed in the signals, bleaching coherent wave packet dynamics in the electronic ground state and a slower component due to relaxation to the S-1 state.
Uploads
Papers by Stephen H Ashworth