The photodecomposition of alkaline aqueous solutions of hypochlorite ion has been investigated using steady state and flash photolysis techniques. At 365 nm the primary products are O(3P), 0-, Cl and C1-formed by the following processesc10-7 with & = 0.28&0.03 and #b = 0.08f0.02. At 313 nm and 253.7 nm O ( l D ) is also produced and the quantum yields are & = 0.075f0.015, $b = 0.127f0.014, c $ ~ = 0.020f0.015 at 313 nm, and & = 0.074-+0.019, 4b = 0.278f0.016, $c = 0.133f0.017 at 253.7 nm.The relative rates of reaction of O(3P) with 02, C10and ClO; have been found to be in the ratios 1 : 2.8 : 15.9. O(3P) reacts with ClOand ClOi by abstraction of 0 as well as by addition. A complete reaction mechanism for the photodecomposition of (210is proposed.

The radiolysis of aqueous solutions of C10-and C10, has been investigated using pulseandsteady state methods. The absorption spectrum of ClO has been identified ( A, , , = 280 nm) and the complete reaction mechanism has been established in the case of C10-and proposed in the case of ClO;. The following rate constants have been evaluated (units of M-l s-l) : e;,+ClO--+ Cl-+O-( 5 . 3 3 1 . 0 ) ~ 1Olo e;,+C10, + CIO-SO-(4.5f0.5)~ 10" OH+ ClO-+ ClO+OH-(9.0f0.5)~ lo9 OH+ClO; -f CIOz+OH-( 6 . 3 5 0 . 5 ) ~ lo9 O-fC10-+ C10+02-(2.4f0.1) x los 2c10 -tCl20z 1.5 x loEo ( 2 4 o-+c10; -+ c102+02-(1.9fO.l)x lo8 Values of the radical and molecular yields obtained for dilute alkaline solution are : G(ei,)+G(H) = 2.92f0.05, G(0H) = 2.41 f0.12, G(H2) = 0.42f0.02 and G(H202) = 0.70f0.01.

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Instrumental neutron activation analysis has been used for the analysis of seven varieties of medicinal herbs generally used by the people of South Asian region. Twenty-one trace elements (essential, toxic and non-essential) were determined. This data should not only be helpful in establishing the base-line values in these medicinal herbs but also in correlating their role as therapeutic agents. A comparison of our data with literature values shows variation in trace element contents of same species of different origin which can be attributed to ecological and geographical variations to some extent; however an exact interpretation demands further extensive investigations.

SummaryEmploying the activation technique in combination with radiochemical separations and high-resolution γ-ray spectroscopy fission neutron spectrum averaged cross sections were measured for several (

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