Good day,

We are experiencing an intermittent fault in the ricc2 module of the Turbomole 7.5 program in which the CC2 (or ADC(2)) equations fail to converge, instead giving bizarre results including 'Infinity', '********************' and 'NaN' (please see attached example). Strangely, the problem can often be alleviated by reducing the number of CPUs assigned to the calculation, but the exact number which will allow the calculation to proceed seems to vary.

If anyone has any advice on how we can overcome this issue it would be greatly appreciated.

Many thanks!