Detecting ion pairing in sodium fluoride solutions with dielectric spectroscopy

M Michael Woodcox (Theiss Research 1 , P.O. Box 127, La Jolla, California 92038,) S Sarah R. Evans (RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,) A Aaron M. Hagerstrom (Communications Technology Laboratory, National Institute of Standards and Technology 4 , 325 Broadway, Boulder, Colorado 80305,) R Rebecca A. Bone (Theiss Research 2 , P.O. Box 127, La Jolla, California 92038,) N Nicholas R. Jungwirth (RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,) S Spencer Mattes (Department of Chemistry and Chemical Biology, Cornell University 5 , 410 Thurston Ave., Ithaca, New York 14850,) A Avik Mahata (Material Measurement Laboratory, National Institute of Standards and Technology 2 , 100 Bureau Dr., Gaithersburg, Maryland 20899,) N Nathan D. Orloff (RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,) C Chris Muzny (Communications Technology Laboratory, National Institute of Standards and Technology 4 , 325 Broadway, Boulder, Colorado 80305,) J James C. Booth (RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,) K Kathleen A. Schwarz (Material Measurement Laboratory, National Institute of Standards and Technology 2 , 100 Bureau Dr., Gaithersburg, Maryland 20899,) A Angela C. Stelson (RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,)

Abstract

The dielectric response of an ionic solution includes ionic diffusion, solvent molecule reorientation, and the intermolecular interactions between solvent, cations, and anions. While ionic diffusion and solvent reorientation produce large responses in the dielectric spectra, the contributions of the ion–ion and ion–water interactions can be difficult to measure and compute. Here, we combine computational and experimental techniques to investigate the impact of ion–ion and ion–water interactions in aqueous sodium fluoride solutions and determine whether an ion pairing peak exists in the dielectric spectra. We use our recently developed direct electric field approach to perform frequency-resolved configurational analysis of ion pairing. From this analysis, we identify a Debye peak associated with the reorientation of ion pairs. Our broadband microwave microfluidic spectra of sodium fluoride solutions further support the existence of a low-frequency Debye relaxation due to ion pairs in the solution.

Article Details

Volume / Issue Vol. 163, Issue 1
Published July 07, 2025
ISSN 0021-9606
Publisher American Institute of Physics

Journal Info

The Journal of Chemical Physics

American Institute of Physics

ISSN: 0021-9606 Physical Sciences

Authors (12)

M

Michael Woodcox

Theiss Research 1 , P.O. Box 127, La Jolla, California 92038,

S

Sarah R. Evans

RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,

A

Aaron M. Hagerstrom

Communications Technology Laboratory, National Institute of Standards and Technology 4 , 325 Broadway, Boulder, Colorado 80305,

R

Rebecca A. Bone

Theiss Research 2 , P.O. Box 127, La Jolla, California 92038,

N

Nicholas R. Jungwirth

RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,

S

Spencer Mattes

Department of Chemistry and Chemical Biology, Cornell University 5 , 410 Thurston Ave., Ithaca, New York 14850,

A

Avik Mahata

Material Measurement Laboratory, National Institute of Standards and Technology 2 , 100 Bureau Dr., Gaithersburg, Maryland 20899,

N

Nathan D. Orloff

RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,

C

Chris Muzny

Communications Technology Laboratory, National Institute of Standards and Technology 4 , 325 Broadway, Boulder, Colorado 80305,

J

James C. Booth

RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,

K

Kathleen A. Schwarz

Material Measurement Laboratory, National Institute of Standards and Technology 2 , 100 Bureau Dr., Gaithersburg, Maryland 20899,

A

Angela C. Stelson

RF Technology Division, National Institute of Standards and Technology 2 , 325 Broadway, Boulder, Colorado 80305,