T
he complex v
ibronic spectra and t
he nonradiative decay dynamics of t
he cyclopropane radical cation (CP
+)are simulated t
heoretically wit
h t
he aid of a time-dependent wave packet propagation approac
h using t
hemultireference time-dependent Hartree sc
heme. T
he t
heoretical results are compared wit
h t
he experimentalp
hotoelectron spectrum of cyclopropane. T
he ground and first excited electronic states of CP
+ are of
2E'and Ã
2E' ' type, respectively. Eac
h of t
hese degenerate electronic states undergoes Ja
hn-Teller (JT) splittingw
hen t
he radical cation is distorted along t
he degenerate v
ibrational modes of e' symmetry. T
he JT splitcomponents of t
hese two electronic states can also undergo pseudo-Ja
hn-Teller (PJT)-type crossings via t
hev
ibrational modes of e' ',
ibe/journals/jpcaf
h/111/i10/eqn/jp0668347e10001.gif"> and
ibe/journals/jpcaf
h/111/i10/eqn/jp0668347e10002.gif"> symmetries. T
hese lead to t
he poss
ibility of multiple multidimensionalconical intersections and
hig
hly nonadiabatic nuclear motions in t
hese coupled manifolds of electronic states.In a previous publication [
J. Phys. Chem. A 2004,
108, 2256], we investigated t
he JT interactions alone in t
he
2E' ground electronic manifold of CP
+. In t
he present work, t
he JT interactions in t
he Ã
2E' ' electronicmanifold are treated, and our previous work is extended by considering t
he coupling between t
he
2E' andÃ
2E' ' electronic states of CP
+. T
he nuclear dynamics in t
his coupled manifold of two JT split doubly degenerateelectronic states is simulated by considering fourteen active and most relevant v
ibrational degrees of freedom.T
he v
ibronic level spectra and t
he ultrafast nonradiative decay of t
he excited cationic states are examinedand are related to t
he
hig
hly complex entanglement of electronic and nuclear degrees of freedom in t
hisprototypical molecular system.