Excited state lifetimes of c(4)('1)Sigma (+)(u), upsilon = 0-2 states of mo
lecular nitrogen have been determined in a laboratory investigation using a
picosecond XUV laser in a pump-probe configuration. For c(4)('1)Sigma (+)(
u) upsilon = 0 the lifetime is tau = 740 +/- 50 ps, for the lowest rotation
al states. For higher rotational states a gradual shift towards tau = 495 p
s is found in agreement with previous findings that these states are subjec
t to predissociation. For c(4)(') Sigma (+)(u) upsilon = 1 no J-dependence
is found and values for two isotopomers are reported: tau = 240 ps for (NN)
-N-14-N-15 = 240 ps for (NN)-N-14-N-15. For c(4)('1)Sigma (+)(u) upsilon =
2 a lifetime for the lowest rotational states (J = 0-3) was derived: tau =
675 +/- 50 ps; for J = 11 a lifetime of tau less than or equal to 120 ps is
deduced. All values for the lifetimes including the J-dependences are expl
ained in a model based on Rydberg-valence interaction. (C) 2001 Elsevier Sc
ience B.V. All rights reserved.