STRONG SALT DEPLETION AT THE SURFACE OF HIGHLY CONCENTRATED AQUEOUS-SOLUTIONS OF CSF, STUDIED BY HEI-UPS

被引：29

作者：

BOHM, R ^{[1
]}

MORGNER, H ^{[1
]}

OBERBRODHAGE, J ^{[1
]}

WULF, M ^{[1
]}

机构：

[1] UNIV WITTEN HERDECKE,INST EXPTL PHYS,STOCKUMER STR 10,D-58448 WITTEN,GERMANY

来源：

SURFACE SCIENCE | 1994年 / 317卷 / 03期

关键词：

D O I：

10.1016/0039-6028(94)90296-8

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We measure He(I) photoelectron spectra from the surface of concentrated aqueous solutions of CsF. The composition ranges from CsF.4.2H2O to CsF.2.6H2O. We find the three bands characteristic for the water orbitals 1b1, 3a1 and 1b2. We evaluate the respective phase transition energy shifts to 1.68, 1.29 and 1.7 eV with an experimental uncertainty of +/- 0.1 eV. Further, we identify signals originating from the ions Cs+ and F-. With the aid of absolute photoionization cross sections it is possible to relate the signal strengths of the ions to those of the water bands. We conclude that the salt concentration is strongly depleted in the surface range accessible by UPS. Assuming a salt-free overlayer we determine its thickness of almost-equal-to 7.5 angstrom (+/- 50%) which would be equivalent to about 2 monolayers of water on top of the highly concentrated bulk phase.

引用

页码：407 / 421

页数：15

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