Rotationally Resolved Photoelectron Angular Distributions from a Nonlinear Polyatomic Molecule

We present, for the first time, rotationally resolved photoelectron images resulting from the ionization of a polyatomic molecule. Photoelectron angular distributions pertaining to the formation of individual rotational levels of $\mathrm{NH}_3{}^{+}$ have been extracted from the images and analyzed to enable a complete determination of the radial dipole matrix elements and relative phases that describe the ionization dynamics. This determination leads to the deduction of significantly different dynamics from those extracted in previous studies which lacked either angular information or rotational resolution.

Figure 1

Raw photoelectron images recorded via the (a) $1_1\to 3_2$ (b) $1_1\to 2_2$ pump transitions and a probe wavelength of 431.3 nm.

Figure 2

Photoelectron spectra extracted from images recorded via the (a) $1_1\to 3_2$ (b) $1_1\to 2_2$ pump transitions (solid line). Corresponding simulated photoelectron spectra using rotational level positions based on the rotational constants taken from Ref. 13, and intensities derived from the ${\beta }_{00}$ values calculated using the matrix elements listed in Table  (dashed line).

Figure 3

Polar plots of photoelectron intensity according to Eq. (1) using the ${\beta }_{\mathrm{LM}}$ values extracted from the pBasex inversion of the images recorded via the (a) $1_1\to 3_2$ (b) $1_1\to 2_2$ pump transitions (solid line) and ${\beta }_{\mathrm{LM}}$ values calculated from the dipole matrix elements listed in Table  (dashed line). For plotting purposes, all PADs are normalized such that ${\beta }_{00}=1$. Errors are derived from pBasex [12] during image analysis.