Inter-channel effects in monosolvated atomic iodide cluster anion detachment: Correlation of the anisotropy parameter with solvent dipole moment

Abstract

Photoelectron imaging results are presented for I(-)[middle dot]X cluster anions (X = CO(2), C(4)H(5)N [pyrrole], (CH(3))(2)CO, CH(3)NO(2)). The available detachment channels are labeled according to the neutral iodine atom states produced (channel I ≡ (2)P(3/2) and channel II ≡ (2)P(1/2)). At photon energies in the vicinity of the channel II threshold these data are compared to previously reported results for I(-)[middle dot]X (X = CH(3)CN, CH(3)Cl, CH(3)Br, and H(2)O). In particular, these results show a strong connection between the dipole moment of the solvent molecule and the behavior of the channel I photoelectron angular distributions in this region, which is consistent with an electronic autodetachment process. The evolution of the channel II:channel I branching ratios in this excitation regime supports this contention.

Photoelectron Angular Distributions as Probes of Cluster Anion Structure: I–·(H2O)2 and I–·(CH3CN)2

“…As has been previously demonstrated, there is a near linear correlation between the dipole moment of the atomic framework of monosolvated cluster anions and Δβ max for channel (A) electrons. 6 Comparison of dihydrated I − cluster anion detachment to these monosolvated results ( Figure 5 closed triangle) shows very good agreement with the trend, strongly suggesting that the correlation is preserved in disolvated cluster anions. The dipole moment for the I·(H 2 O) 2 cluster framework (in the limit of vertical excitation) 7 was calculated via Gaussian 03 32 at the MP2 level and the aug-cc-pvdz basis set 33 for all atoms except I, for which we used the CRENBL pseudopotential and basis set.…”

“…6 It is no coincidence that the maximum in β(eKE) is 150 meV below the channel B threshold, the same difference as that between the PNS1 and PES2 maxima for channel A. The excited [I( 2 P 1/2 )·(CH 3 CN) 2 ] − state can be thought of as analogous to the one responsible for the PNS1 band, which is a dipole bound state associated with the ground state [I( 2 P 3/2 )·(CH 3 CN) 2 ] framework .…”

Near-threshold electron transfer in anion-nucleobase clusters: does the identity of the anion matter?

“…Indeed, if we focus on the Iaction spectrum, band I appears clearly at ~4.2 eV with band II at ~5.2 eV, leading us to assign these features to the two spin-orbit states of the neutral cluster ( 2 P1/2 and 2 P3/2, respectively), which are separated by 0.94 eV for iodine [16,30]. Band II in the photofragmentation spectrum is therefore assigned as arising from direct detachment from the dipole-bound excited state built on the upper ( 2 P1/2) spin-orbit state of I [18,40].…”

Decay dynamics of nascent acetonitrile and nitromethane dipole-bound anions produced by intracluster charge-transfer

“…37,38 The I − • CH 3 NO 2 complex studied here has previously been investigated by photofragment action spectroscopy 39 and photoelectron imaging. 40 The action spectroscopy experiments, in which anionic and neutral fragments were detected as functions of excitation energy, yielded an electronic absorption spectrum of the complex peaking just below 3.60 eV, the VDE of the initial complex. The electronic band was attributed to a dipole-bound excited state of the complex, which was observed to decay to CH 3 NO 2 − as well as I − and NO 2 − .…”