| Summary: | In this work we have measured photoelectron angular distributions (PADs) from small polyatomic molecules in the weak-field limit. We have conducted experiments in a variety of multiphoton schemes in different polarization geometries with a view to gaining insight into molecular photoionization dynamics. In particular, we have performed novel experiments using the techniques of strong-field alignment and photoelectron circular dichroism.
The use of a strong-field alignment pulse has enabled us to approach a molecular frame measurement in the two-photon ionization of aniline and naphthalene. We have compared our measured PADs with calculations performed using the ePolyScat package. In the case of naphthalene good agreement is observed with molecular frame simulations, but in the case of aniline the experimental results cannot be reproduced by the calculations. This is attributed to perturbation of the ionization process by the alignment pulse in the case of aniline.
Multiphoton photoelectron circular dichroism (MP-PECD) has been used to study the chiral monoterpenes α-pinene, 3-carene and fenchone. MP-PECD experiments performed with table-top femtosecond UV laser sources have previously been shown to enhance the chiral anisotropy observable in one-photon schemes. In this work we use a picosecond laser source which has enabled us in addition to unravel the vibronic dependence of the photoionization dynamics.
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