Microsolvation of Sodium Thiocyanate in Water: Gas Phase Anion Photoelectron Spectroscopy and Theoretical Calculations

Shiyan Gong; Peng Wang; Zhiyou Wei; Bin Yang; Xiling Xu; Hongguang Xu; Weijun Zheng

doi:10.1021/acs.jpca.0c07071

Microsolvation of Sodium Thiocyanate in Water: Gas Phase Anion Photoelectron Spectroscopy and Theoretical Calculations

J Phys Chem A. 2020 Sep 24;124(38):7816-7826. doi: 10.1021/acs.jpca.0c07071. Epub 2020 Sep 10.

Authors

Shiyan Gong^{1

2}, Peng Wang^{1

2}, Zhiyou Wei^{1

2}, Bin Yang^{1

2}, Xiling Xu^{1

2}, Hongguang Xu^{1

2}, Weijun Zheng^{1

2}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.

PMID: 32852950
DOI: 10.1021/acs.jpca.0c07071

Abstract

We studied NaSCN(H₂O)_n^- clusters in the gas phase using size-selected anion photoelectron spectroscopy. Vertical detachment energies (VDEs) of NaSCN(H₂O)_n^- (n = 0-6) clusters were obtained in the experiment. Structures of NaSCN(H₂O)_n^- (n = 0-6) clusters and their corresponding neutral counterparts were investigated by theoretical calculations. Our studies show that the Na-NCS type of structures rather than the Na-SCN type of structures are dominant in the gas phase for both anionic and neutral NaSCN(H₂O)_n clusters. For NaSCN(H₂O)_n^- anions, the contact ion pair (CIP) and solvent-separated ion pair (SSIP) type of structures coexist at n = 2 and 3, the SSIP type of structures become dominant at n ≥ 4. For neutral NaSCN(H₂O)_n, the CIP type of structures are dominant from n = 1 to 6 and the SSIP type of structures start to appear at n = 6. The gas phase structures in this work support the existence of ion clustering in concentrated NaSCN aqueous solutions.