TITLE

Electronic and chemical changes in shocked liquid carbon disulfide inferred from time resolved reflection experiments and analysis

AUTHOR(S)
Gustavsen, R.; Gupta, Y. M.
PUB. DATE
July 1991
SOURCE
Journal of Chemical Physics;7/1/1991, Vol. 95 Issue 1, p451
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Time resolved, spectroscopic reflection measurements (300–500 nm) have been used to examine the electronic and chemical changes in liquid carbon disulfide shocked to peak pressures as high as 110 kbar. Multiple-shock loading and unloading and double-shock experiments were performed to examine the influence of temperature, and to compare the present data with previous absorption and continuum measurements. The reflectance increases markedly with pressure in multiple-shock loading experiments. At 300 nm, the reflectance increases from less than 0.33% at ambient conditions to 10% at 105 kbar. However, the reflectance changes exhibit wavelength dependence, being smaller for longer wavelengths, and are reversible upon pressure unloading. A phenomenological model was developed to calculate the complex refractive index for carbon disulfide. This model in conjunction with Fresnel’s reflection equations can be used to analyze the multiple-shock reflection and absorption data in a consistent manner. The experimental results can be understood in terms of the growth of absorption bands due to increasing overlap of the π electron wave functions of neighboring molecules due to compression; this overlap is likely a precursor to associative chemical reactions. The complete reversal in reflectance at pressures above 90 kbar is in contrast to the absorption data and arises because the present reflection measurements do not sample the bulk material, but, instead, are collected from a very thin, cooled, unreacted layer of carbon disulfide. The double-shock experiments show no evidence of a chemical reaction below 90 kbar and are in agreement with multiple-shock data. At higher pressures, the double-shock experiments show evidence of chemical reactions and display a complicated reflectance history that depends markedly on the wavelength. The wavelength dependence and associated complexities in the double-shock experiments are consequences of pressure dependent...
ACCESSION #
7616164

 

Related Articles

  • Novel wide-band time-resolved photoreflectance measurement technique. Pires, M. Pamplona; Souza, P.L. // Applied Physics Letters;7/4/1994, Vol. 65 Issue 1, p88 

    Presents a wide-band time-resolved photoreflectance measurement technique. Advantage of eliminating in a natural way any undesirable photoluminescence or background signal; Sources of parameters for carrier dynamics studies; Implications for the change in reflectivity due to band-filling effects.

  • Time-resolved reflectivity studies of the GaAs(100)/oxide and GaAs(100)/ZnSe interface. Cheville, R.A.; Haynes, W.B.; Halas, N.J. // Applied Physics Letters;9/16/1991, Vol. 59 Issue 12, p1476 

    Analyzes a series of subpicosecond time-resolved reflectivity measurements in n-type gallium arsenide (GaAs) interfaces at photoexcitation densities. Dependence of reflectivity signal to interface preparation; Preparation of GaAs surface; Changes in the space-charge field of GaAs.

  • REFLECTIONS ON THE LAW. BRANDS, G. // Alberta Views;Jun2014, Vol. 17 Issue 5, p17 

    A photograph focused on the reflection of an image in Alberta is presented.

  • 1B2(1Σu+) excited state decay dynamics in CS2. Townsend, Dave; Satzger, Helmut; Ejdrup, Tine; Lee, Anthony M. D.; Stapelfeldt, Henrik; Stolow, Albert // Journal of Chemical Physics;12/21/2006, Vol. 125 Issue 23, p234302 

    The authors report time resolved photoelectron spectra of the 1B2(1Σu+) state of CS2 at pump wavelengths in the region of 200 nm. In contrast to previous studies, the authors find that the predissociation dynamics is not well described by a single exponential decay. Biexponential modeling of...

  • ZnSe/GaAs interface state probed by time-resolved reflectance difference spectroscopy. Wong, K.S.; Wang, H. // Applied Physics Letters;6/14/1999, Vol. 74 Issue 24, p3663 

    Applies time-resolved reflectance difference spectroscopy (TRDS) to study the dynamics and relaxation processes of the zinc selenide (ZnSe)/gallium arsenide (GaAs) interface state associated with Zn-As bonds. Rapid cooling of hot carrier in the spectral region above the ZnSe band edge;...

  • Coherent phonon dynamics at the martensitic phase transition of Ni2MnGa. Mariager, S. O.; Caviezel, A.; Beaud, P.; Quitmann, C.; Ingold, G. // Applied Physics Letters;6/25/2012, Vol. 100 Issue 26, p261911 

    We use time-resolved optical reflectivity to study the laser stimulated dynamics in the magnetic shape memory alloy Ni2MnGa. We observe two coherent optical phonons, at 1.2 THz in the martensite phase and at 0.7 THz in the pre-martensite phase, which we interpret as a zone-folded acoustic phonon...

  • Transient thermoreflectance of thin metal films in the picosecond regime. Miklós, András; Lőrincz, András // Journal of Applied Physics;4/1/1988, Vol. 63 Issue 7, p2391 

    Presents a study which investigated the distribution nature of the reflection process for pump-and-probe-type picosecond transient thermoreflectance measurements (PTTR). Approximation for the temporal dependence of the reflectivity for temperature distributions; Problem of determining the...

  • Diffuse reflectivity of Tyvek in water. Anisotropical effects. Arteaga Vela´zquez, J. C.; Va´zquez-Lo´pez, C.; Zepeda, A. // AIP Conference Proceedings;2001, Vol. 566 Issue 1, p350 

    The reflectivity of Tyvek in air and water as a function of the incidence and reflection angles is reported. The measurements were made for λ = 488nm. Optical anisotropies of the material are revealed when a rotation is made about the normal vector of the sample.

  • Light-Reflection Strategies. Parker, Andrew R. // American Scientist;May/Jun99, Vol. 87 Issue 3, p248 

    Compares the reflective properties of naturally occurring structures to human designs. Features of Stealth planes; Application of the principle of bioluminescent ventral photophores; Description of the ommatidia of insects.

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics