The Molecular Surface Structure of Ammonium and Potassium Dinitramide: A Vibrational Sum Frequency Spectroscopy and Quantum Chemical Study

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• 作者：Martin Rahm ; Eric Tyrode ; Tore Brinck ; C. Magnus Johnson
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：June 2, 2011
• 年：2011
• 卷：115
• 期：21
• 页码：10588-10596
• 全文大小：908K
• 年卷期：v.115,no.21(June 2, 2011)
• ISSN：1932-7455

文摘

Vibrational sum frequency spectroscopy (VSFS) and quantum chemical modeling have been employed to investigate the molecular surface structure of ammonium and potassium dinitramide (ADN and KDN) crystals. Identification of key vibrational modes was made possible by performing density functional theory calculations of molecular clusters. The surface of KDN was found to be partly covered with a thin layer of the decomposition product KNO₃, which due to its low thickness was not detectable by infrared and Raman spectroscopy. In contrast, ADN exhibited an extremely inhomogeneous surface, on which polarized dinitramide anions were present, possibly together with a thin layer of NH₄NO₃. The intertwined use of theoretical and experimental tools proved indispensable in the analysis of these complex surfaces. The experimental verification of polarized and destabilized dinitramide anions stresses the importance of designing surface-active polymer support, stabilizers, and/or coating agents, in order to enable environmentally friendly ADN-based solid-rocket propulsion.