Related Experiment Video
Updated: Jun 28, 2026
10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Dynamic properties of angle-dependent high-order harmonic generation from coherently rotating molecules
Kazumichi Yoshii1, Godai Miyaji, Kenzo Miyazaki
1Advanced Laser Science Research Section, Institute of Advanced Energy, Kyoto University, Kyoto 611-0011, Japan.
Physical Review Letters
|November 13, 2008
Summary
High-order harmonic generation in nitrogen (N2) and oxygen (O2) molecules was studied. Results match theoretical predictions, highlighting the importance of molecular alignment for probing electronic dynamics.
Area of Science:
- Molecular physics
- Quantum optics
- Laser-matter interactions
Background:
- High-order harmonic generation (HHG) is a key process for creating extreme ultraviolet and X-ray light.
- Understanding molecular response to intense laser fields is crucial for attosecond science.
Purpose of the Study:
- To investigate high-order harmonic generation from coherently rotating nitrogen (N2) and oxygen (O2) molecules.
- To explore the influence of molecular alignment on harmonic emission characteristics.
Main Methods:
- Femtosecond laser pump-probe experiments were employed.
- Measurements were conducted at various molecular alignment angles.
- Results were compared with theoretical calculations from a novel theory.
Main Results:
- Angle-dependent high-order harmonic generation was successfully observed in N2 and O2.
- Experimental data showed excellent agreement with theoretical predictions.
- The study confirmed characteristic properties of angle-dependent harmonic generation.
Conclusions:
- Molecular alignment and polarization geometry are critical factors in HHG.
- HHG in aligned molecules offers a promising route for probing molecular electronic structure and dynamics.
- This work validates theoretical models and opens avenues for advanced molecular spectroscopy.
Related Concept Videos
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:27¹H NMR: Long-Range Coupling
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to the...
According to Hooke's law, the vibrational frequency is directly proportional to the...