@article{a870d98259db4c1cac66ce10b71236bd,
title = "Pressure-Induced polymerization of LiN(CN)2",
abstract = "The high-pressure behavior of lithium dicyanamide (LiN-(CN)2) was studied with in situ Raman and infrared (IR) spectroscopies, and synchrotron angle-dispersive powder X-ray diffraction (PXRD) in a diamond anvil cell (DAC) to 22 GPa. The fundamental vibrational modes associated with molecular units were assigned using a combination of experimental data and density functional perturbation theory. Some low-frequency modes were observed for the first time. On the basis of spectroscopic and diffraction data, we suggest a polymorphic phase transformation at ∼8 GPa, wherein dicyanamide ions remain as discrete molecular species. Above ca. 18 GPa, dicyanamide units polymerize, forming a largely disordered network, and the extent of polymerization May be increased by annealing at elevated temperature. The polymerized product consists of tricyanomelaminate-like groups containing sp2-hybidized carbon−nitrogen bonds and exhibits a visible absorption edge near 540 nm. The product is recoverable to ambient conditions but is not stable in air/ moisture.",
author = "Keefer, {Derek W.} and Huiyang Gou and Purdy, {Andrew P.} and Albert Epshteyn and Kim, {Duck Young} and Badding, {John V.} and Strobel, {Timothy A.}",
note = "Funding Information: We thank J. Smith and R. Hrubiak for assistance with XRD measurements. This work was supported by DARPA under ARO Contract No. 31P4Q- 3-I-0005. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357. D.Y.K. acknowledges the Texas Advanced Computing Center (TACC) at the University of Texas at Austin and Argonne Leadership Computing Facility (ALCF) which is a DOE Office of Science User Facility supported under Contract No. DEAC02-06CH11357 for providing high-performance computing resources and the support of NSAF Grant No. U1530402. Funding Information: We thank J. Smith and R. Hrubiak for assistance with XRD measurements. This work was supported by DARPA under ARO Contract No. 31P4Q-3-I-0005. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357. D.Y.K. acknowledges the Texas Advanced Computing Center (TACC) at the University of Texas at Austin and Argonne Leadership Computing Facility (ALCF) which is a DOE Office of Science User Facility supported under Contract No. DEAC02-06CH11357 for providing high-performance computing resources and the support of NSAF Grant No. U1530402. Publisher Copyright: {\textcopyright} 2016 American Chemical Society.",
year = "2016",
month = dec,
doi = "10.1021/acs.jpca.6b06780",
language = "English (US)",
volume = "120",
pages = "9370--9377",
journal = "Journal of Physical Chemistry A",
issn = "1089-5639",
publisher = "American Chemical Society",
number = "47",
}