Reconstruction of two-dimensional molecular structure with laser-induced electron diffraction from laser-aligned polyatomic molecules.

Chao Yu,C D Lin,Hui Wei,Xu Wang,Ruifeng Lu,Anh-Thu Le

doi:10.1038/srep15753

Abstract

Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics. Based on laser-induced electron diffraction and partial one-dimensional molecular alignment, here we provide two effective methods for reconstructing two-dimensional structure of polyatomic molecules. We demonstrate that electron diffraction images in both scattering angles and broadband energy can be utilized to retrieve complementary structure information, including positions of light atoms. With picometre spatial resolution and the inherent femtosecond temporal resolution of lasers, laser-induced electron diffraction method offers significant opportunities for probing atomic motion in a large molecule in a typical pump-probe measurement.

Highlights

Molecules can be reconstructed from such scattering images, LIED can be used for dynamic imaging with few- to tens femtoseconds temporal resolutions since infrared lasers with such pulse durations are already available in many laboratories
It shows that LIED will work as conventional electron diffraction (CED) if the returning electron energies are on the order of about 100–300 eV and if the diffraction images are taken at backscattered angles
The first experimental demonstration of LIED was carried out for isotropically distributed N2 and O2 molecules with 2-micron lasers by Blaga et al.[17]. They retrieved N-N bond length in agreement with the known neutral N2 distance within the estimated resolution of 0.05 Å, but the O-O bond length was found to be 0.1 Å shorter than the neutral O2 bond length. The latter was attributed to the readjustment of O-O bond length within the 5 fs that takes the electron to return to collide with the molecular ion after tunnel ionization, providing the first evidence of sub-angstrom spatial and few-femtosecond temporal resolution with LIED

Summary

Introduction

Molecules can be reconstructed from such scattering images, LIED can be used for dynamic imaging with few- to tens femtoseconds temporal resolutions since infrared lasers with such pulse durations are already available in many laboratories. It shows that LIED will work as CED if the returning electron energies are on the order of about 100–300 eV and if the diffraction images are taken at backscattered angles.

Results

Conclusion