Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid

The UV-spectroscopic behavior of KI dissolved in supercritical ammonia enabled us to identify two species that contribute to the optical absorption depending on the fluid density ρ1 and the temperature T. At low ρ1 and high T, contact ion pairs (CIPs) prevail, while at high density of ammonia, solve...

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Autores principales:	Sciaini, Alberto Germán, Marceca, Ernesto Jose, Fernandez Prini, Roberto
Publicado:	2005
Materias:	Charge transfer Density (specific gravity) Dissolution Ground state Light absorption Positive ions Ultraviolet radiation Excited states Fluid density Ion pairing Supercritical ammonia Supercritical fluids
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v109_n40_p18949_Sciaini http://hdl.handle.net/20.500.12110/paper_15206106_v109_n40_p18949_Sciaini
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_15206106_v109_n40_p18949_Sciaini
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spelling	paper:paper_15206106_v109_n40_p18949_Sciaini2023-06-08T16:18:54Z Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid Sciaini, Alberto Germán Marceca, Ernesto Jose Fernandez Prini, Roberto Charge transfer Density (specific gravity) Dissolution Ground state Light absorption Positive ions Ultraviolet radiation Excited states Fluid density Ion pairing Supercritical ammonia Supercritical fluids The UV-spectroscopic behavior of KI dissolved in supercritical ammonia enabled us to identify two species that contribute to the optical absorption depending on the fluid density ρ1 and the temperature T. At low ρ1 and high T, contact ion pairs (CIPs) prevail, while at high density of ammonia, solvent separated ion pairs (SSIPs) and free iodide ions dominate the optical absorption of the solute. The features of the electron excitation process depend on the state of the K+I- species present. Starting with isolated KI in the vapor, where the process is an interionic charge transfer, when the CIP becomes solvated the UV absorption shifts strongly to the blue. As ρ1 increases, the amounts of SSIP and of free iodide increase progressively and their electronic excited states become those characteristic of the charge-transfer-to-solvent process. This study suggests there is a strong influence of the cation on the electronic transition of dissolved iodide when it is forming CIPs. Moreover, the fact that K+-NH3 interaction is much larger than that of I --NH3 suggests that the electronic photoinduced excited state of CIPs is similar to the ground state observed for alkali metals in NH3 clusters. © 2005 American Chemical Society. Fil:Sciaini, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Marceca, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Fernández-Prini, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2005 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v109_n40_p18949_Sciaini http://hdl.handle.net/20.500.12110/paper_15206106_v109_n40_p18949_Sciaini
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Charge transfer Density (specific gravity) Dissolution Ground state Light absorption Positive ions Ultraviolet radiation Excited states Fluid density Ion pairing Supercritical ammonia Supercritical fluids
spellingShingle	Charge transfer Density (specific gravity) Dissolution Ground state Light absorption Positive ions Ultraviolet radiation Excited states Fluid density Ion pairing Supercritical ammonia Supercritical fluids Sciaini, Alberto Germán Marceca, Ernesto Jose Fernandez Prini, Roberto Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
topic_facet	Charge transfer Density (specific gravity) Dissolution Ground state Light absorption Positive ions Ultraviolet radiation Excited states Fluid density Ion pairing Supercritical ammonia Supercritical fluids
description	The UV-spectroscopic behavior of KI dissolved in supercritical ammonia enabled us to identify two species that contribute to the optical absorption depending on the fluid density ρ1 and the temperature T. At low ρ1 and high T, contact ion pairs (CIPs) prevail, while at high density of ammonia, solvent separated ion pairs (SSIPs) and free iodide ions dominate the optical absorption of the solute. The features of the electron excitation process depend on the state of the K+I- species present. Starting with isolated KI in the vapor, where the process is an interionic charge transfer, when the CIP becomes solvated the UV absorption shifts strongly to the blue. As ρ1 increases, the amounts of SSIP and of free iodide increase progressively and their electronic excited states become those characteristic of the charge-transfer-to-solvent process. This study suggests there is a strong influence of the cation on the electronic transition of dissolved iodide when it is forming CIPs. Moreover, the fact that K+-NH3 interaction is much larger than that of I --NH3 suggests that the electronic photoinduced excited state of CIPs is similar to the ground state observed for alkali metals in NH3 clusters. © 2005 American Chemical Society.
author	Sciaini, Alberto Germán Marceca, Ernesto Jose Fernandez Prini, Roberto
author_facet	Sciaini, Alberto Germán Marceca, Ernesto Jose Fernandez Prini, Roberto
author_sort	Sciaini, Alberto Germán
title	Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
title_short	Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
title_full	Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
title_fullStr	Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
title_full_unstemmed	Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid
title_sort	influence of ion pairing on the uv-spectral behavior of ki dissolved in supercritical nh3: from vapor phase to condensed liquid
publishDate	2005
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v109_n40_p18949_Sciaini http://hdl.handle.net/20.500.12110/paper_15206106_v109_n40_p18949_Sciaini
work_keys_str_mv	AT sciainialbertogerman influenceofionpairingontheuvspectralbehaviorofkidissolvedinsupercriticalnh3fromvaporphasetocondensedliquid AT marcecaernestojose influenceofionpairingontheuvspectralbehaviorofkidissolvedinsupercriticalnh3fromvaporphasetocondensedliquid AT fernandezpriniroberto influenceofionpairingontheuvspectralbehaviorofkidissolvedinsupercriticalnh3fromvaporphasetocondensedliquid
_version_	1768543199542902784

Influence of ion pairing on the UV-spectral behavior of KI dissolved in supercritical NH3: From vapor phase to condensed liquid

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