Double beta decay of Mo-100 to the excited states of daughter nuclei has been studied using a 600 cm(3) low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic (100)mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of Mo-100. The half-life for the two-neutrino double beta decay of Mo-100 to the excited 0(1)(+) state in Ru-100 is measured to be T-1/2 = [7.5 +/- 0.6(stat) +/- 0.6(syst)] . 10(20) yr. For other (0 nu + 2 nu) transitions to the 2(1)(+), 2(2)(+), 0(2)(+), 2(3)(+) and 0(3)(+) levels in Ru-100, limits are obtained at the level of similar to(0.25-1.1) . 10(22) yr. (C) 2014 Elsevier B.V. All rights reserved.
