Solvation effects on angular distributions in H−(NH3)n and NH2−(NH3)n photodetachment: Role of solute electronic structure

Abstract

We report 355 and 532 nm photoelectron imaging results for H(-)(NH(3))(n) and NH(2)(-)(NH(3))(n), n = 0-5. The photoelectron spectra are consistent with the electrostatic picture of a charged solute (H(-) or NH(2)(-)) solvated by n ammonia molecules. For a given number of solvent molecules, the NH(2)(-) core anion is stabilized more strongly than H(-), yet the photoelectron angular distributions for solvated H(-) deviate more strongly from the unsolvated limit than those for solvated NH(2)(-). Hence, we conclude that solvation effects on photoelectron angular distributions are dependent on the electronic structure of the anion, i.e., the type of the initial orbital of the photodetached electron, rather than merely the strength of solvation interactions. We also find evidence of photofragmentation and autodetachment of NH(2)(-)(NH(3))(2-5), as well as autodetachment of H(-)(NH(3))(5), upon 532 nm excitation of these species.

Photoelectron angular distributions in negative-ion photodetachment from mixed sp states

“…47 The model prediction compares favorably with the experimental data; however, it is not too different from the prediction of the unmodified (f = 1) WBCZ model (grey curve in Figure 3(b)). …”

“…The H − and NH 2 − anions, respectively, solvated by ammonia, are excellent trial systems for this model. In the accompanying paper, 47 we reported our recent experimental results for the H − (NH 3 ) n and NH 2 − (NH 3 ) n cluster anions. Here, we use the formalism developed in Sec.…”

“…47 The non-bonding b 1 HOMO of unsolvated NH 2 − is essentially a p orbital on the nitrogen atom. Upon solvation, the electron density within the anion should be perturbed along the solvent-ion interaction axis, in general breaking the ungerade symmetry of the orbital.…”

“…In Sec. III, we compare the model predictions to experimental data for strongly solvated H − and NH 2 − anions, 47 corresponding to the strongly perturbed, predominantly s and predominantly p parent states, respectively.…”

Communication: Photoelectron angular distributions of CH− reveal a temporary anion state

“…[1][2][3][4][5][6][7][8][9][10] In addition to measuring traditional photoelectron spectra, the imaging experiment also provides an extra set of information, the photoelectron angular distributions (PADs). The PAD carries information about the parent ion orbital from which the electron is detached.…”