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

Yu C, Wei H, Wang X, Le AT, Lu R, Lin CD - Sci Rep (2015)

Bottom Line: Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, PR China.

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.

No MeSH data available.


Related in: MedlinePlus

2D diffraction images and reconstructed 2D molecular structures from perfectly 1D aligned CF4 (left column) and ClCF3 (right column).The molecules are aligned parallel to the direction of the broadband (100–300 eV) electron beam. (a,b) Diffraction images in polar coordinates; (c,d) Diffraction images in two-component momentum transfer coordinates; (e,f) 2D Fourier transformed molecular structures.
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f3: 2D diffraction images and reconstructed 2D molecular structures from perfectly 1D aligned CF4 (left column) and ClCF3 (right column).The molecules are aligned parallel to the direction of the broadband (100–300 eV) electron beam. (a,b) Diffraction images in polar coordinates; (c,d) Diffraction images in two-component momentum transfer coordinates; (e,f) 2D Fourier transformed molecular structures.

Mentions: Figure 3(a,b) show the 2D MCF, γ(p,θ), for perfectly 1D aligned CF4 and ClCF3, respectively. We keep the range of MCF to scattering angle θ > 60° only. In Fig. 3(c,d), the MCF is expressed in (qz, q⊥) using the relation: and . Here qz is parallel to the molecular axis, and q⊥ perpendicular to it. The 2D Fourier transform is then used to obtain the 2D molecular structure of CF4 and ClCF3, shown in Fig. 3(e,f), respectively. Unlike the first method, the most effective angular region is found to be between 120° < θ < 180° in this method. Thus the F-F peak is stronger than the weak F-C peak in Fig 3(e) for CF4. For ClCF3 the Cl-F peak is stronger than the F-C peak. At angles larger than 120°, Fig. 1(c) [or Supplementary Fig. S3] shows that the DCS decreases in the order of Cl, F and C. Thus C is more difficult to be observed for the present cases with this method. The result illustrates our assertion that bond lengths extracted at different collision energy and/or different scattering angles can provide complimentary structure information. Some bond lengths that are not easily visible using method 1 can be more clearly seen using method 2, and vice versa.


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

Yu C, Wei H, Wang X, Le AT, Lu R, Lin CD - Sci Rep (2015)

2D diffraction images and reconstructed 2D molecular structures from perfectly 1D aligned CF4 (left column) and ClCF3 (right column).The molecules are aligned parallel to the direction of the broadband (100–300 eV) electron beam. (a,b) Diffraction images in polar coordinates; (c,d) Diffraction images in two-component momentum transfer coordinates; (e,f) 2D Fourier transformed molecular structures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4621501&req=5

f3: 2D diffraction images and reconstructed 2D molecular structures from perfectly 1D aligned CF4 (left column) and ClCF3 (right column).The molecules are aligned parallel to the direction of the broadband (100–300 eV) electron beam. (a,b) Diffraction images in polar coordinates; (c,d) Diffraction images in two-component momentum transfer coordinates; (e,f) 2D Fourier transformed molecular structures.
Mentions: Figure 3(a,b) show the 2D MCF, γ(p,θ), for perfectly 1D aligned CF4 and ClCF3, respectively. We keep the range of MCF to scattering angle θ > 60° only. In Fig. 3(c,d), the MCF is expressed in (qz, q⊥) using the relation: and . Here qz is parallel to the molecular axis, and q⊥ perpendicular to it. The 2D Fourier transform is then used to obtain the 2D molecular structure of CF4 and ClCF3, shown in Fig. 3(e,f), respectively. Unlike the first method, the most effective angular region is found to be between 120° < θ < 180° in this method. Thus the F-F peak is stronger than the weak F-C peak in Fig 3(e) for CF4. For ClCF3 the Cl-F peak is stronger than the F-C peak. At angles larger than 120°, Fig. 1(c) [or Supplementary Fig. S3] shows that the DCS decreases in the order of Cl, F and C. Thus C is more difficult to be observed for the present cases with this method. The result illustrates our assertion that bond lengths extracted at different collision energy and/or different scattering angles can provide complimentary structure information. Some bond lengths that are not easily visible using method 1 can be more clearly seen using method 2, and vice versa.

Bottom Line: Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, PR China.

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.

No MeSH data available.


Related in: MedlinePlus