Is the Hexacyanoferrate(II) Anion Stable in Aqueous Solution? A Combined Theoretical and Experimental Study

A combined theoretical and experimental study was performed to elucidate the structural and dynamical properties of the isolated aqueous hexacyanoferrate(II) ion as well as in the presence of potassium counterions. It is shown that in absence of counterions, the highly negatively charged hexacyanoferrate(II) complex is not stable in aqueous solution. However, if the high negative charge is compensated by potassium counterions, a stable complex is observed, which is proven by theoretical simulations as well as by extended X-ray absorption fine structure (EXAFS) experiments. From the simulation it is found that potassium ions surrounding the complex are highly mobile and thus cannot be observed via EXAFS experiments. The structure of aqueous hexacyanoferrate(II) in the presence of potassium ions is identical to that of the solid-state structure, but the mobility of potassium ions is significantly increased in the liquid. These highly mobile potassium ions circulating the complex are the reason for the very short lifetime of hydrogen bonds between solvent water molecules and cyanide ligands being on the femtosecond scale

Time properties of MWPC using electronegative gases, and their efficiency of detection for normal and abnormal particles (quarks)

The efficiency for detection of fractionally charged particles of multiwire proportional chambers using electronegative gases has been investigated, using a model to simulate the ion production and drift in a MWPC and comparing the results with experimental data. (10 refs)

A search for fractionally charged particles at the CERN intersecting storage rings

Final results of a search for fractionally charged particles at the CERN Intersecting Storage Rings are reported. Several independent scintillation counter, multiwire proportional chamber telescopes simultaneously sampled c.m. production angles from 0 degrees to 90 degrees . The experiment was sensitive to particles of electric charge in the range 0.1e< mod Q mod <0.8e, with velocities greater than 0.25c and with masses up to, in principle, 47 GeV/c/sup 2/. No such particles were observed among the products of 1.2*10/sup 10/ proton- proton interactions at s=2830 GeV/sup 2/. The cross section limit for the production of quark-antiquark pairs of charge mod Q mod =/sup 1 ///sub 3/e or /sup 2///sub 3/e in the reaction pp to ppqq, at s=2830 GeV/sup 2/, is sigma <or approximately=8*10/sup -35/ cm/sup 2/ for quark masses up to approximately 20 GeV/c/sup 2/. (30 refs)

A search for quarks at the CERN intersecting storage rings

No quark candidates have been seen among 0.6*10/sup 9/ charged particles at the ISR. The corresponding cross section limit for charge /sup 1///sub 2/(/sup 2///sub 3/) is <or=3(6)*10/sup -34/ cm/sup 2/ for quark masses up to 22(13) GeV, assuming (P/sub T/)=0.4 GeV/c. (9 refs)