Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Jul 10;4(Pt 5):555-559.
doi: 10.1107/S2052252517009344. eCollection 2017 Sep 1.

Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode

Chenyang Shi  1 , Rattavut Teerakapibal  2 , Lian Yu  2 , Geoff G Z Zhang  1
Affiliations

Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode

Chenyang Shi et al. IUCrJ. .

Abstract

Using high-brilliance high-energy synchrotron X-ray radiation, for the first time the total scattering of a thin organic glass film deposited on a strongly scattering inorganic substrate has been measured in transmission mode. The organic thin film was composed of the weakly scattering pharmaceutical substance indomethacin in the amorphous state. The film was 130 µm thick atop a borosilicate glass substrate of equal thickness. The atomic pair distribution function derived from the thin-film measurement is in excellent agreement with that from bulk measurements. This ability to measure the total scattering of amorphous organic thin films in transmission will enable accurate in situ structural studies for a wide range of materials.

Keywords: amorphous organic thin films; indomethacin; pair distribution functions; transmission X-ray scattering.

PubMed Disclaimer

Figures

Figure 1
Figure 1
(a) Preparation of an IMC thin film. (b) Experimental setup for thin-film X-ray scattering measurements in transmission. The sample can be rotated if necessary.
Figure 2
Figure 2
(a) Raw diffraction intensities for the thin-film sample including the substrate and for the substrate itself. (b) Diffraction intensities for the thin film only from four independent measurements. The 10 min runs were scaled to compare with the 30 min run. (c) The scattering signals for a-IMC from the tube (blue) and the thin-film (red) methods. The thin-film signal was scaled to match the signal from the tube method.
Figure 3
Figure 3
F(Q) for a-IMC obtained from thin-film and bulk measurements. For reference, the F(Q) for c-IMC (γ polymorph) is also shown.
Figure 4
Figure 4
PDFs of crystalline and amorphous IMC plotted over r ranges of (a) up to 80 Å and (b) up to 20 Å. The measured crystalline PDF is also plotted as a reference.
See this image and copyright information in PMC

References

    1. Bates, S., Zografi, G., Engers, D., Morris, K., Crowley, K. & Newman, A. (2006). Pharm. Res. 23, 2333–2349. - PubMed
    1. Bauers, S. R., Wood, S. R., Jensen, K. M. Ø., Blichfeld, A. B., Iversen, B. B., Billinge, S. J. L. & Johnson, D. C. (2015). J. Am. Chem. Soc. 137, 9652–9658. - PubMed
    1. Benmore, C. J. & Weber, J. K. R. (2011). Phys. Rev. X, 1, 011004.
    1. Chupas, P. J., Qiu, X., Hanson, J. C., Lee, P. L., Grey, C. P. & Billinge, S. J. L. (2003). J. Appl. Cryst. 36, 1342–1347.
    1. Dawson, K., Kopff, L. A., Zhu, L., McMahon, R. J., Yu, L., Richert, R. & Ediger, M. D. (2012). J. Chem. Phys. 136, 094505. - PubMed