PDF Publication Title:
Text from PDF Page: 073
Chapter 3 – Raman Spectroscopy of Graphene and Graphene-based Strain Sensors Typically the interaction of a photon with a molecule excites the molecule to a temporary virtual state. Upon relaxation, the corresponding photon gets emitted to certain vibrational state and can have three different possibilities (Figure 3.1b): Rayleigh (elastic) scattering - The incident and emitted photon have the same energy Stokes Raman scattering - The molecule absorbs energy through the creation of a phonon and thus the emitted photon shifts to lower frequency than the incident photon anti-Stokes Raman scattering - The molecule loses energy through the absorption of a phonon and thus the emitted photon shifts to higher frequency than the incident photon Raman spectroscopy is a type of vibrational spectroscopy, and these energy differences arise from the molecular vibrations. Moreover, the intensity of Raman bands depends on the number of molecules present in different vibrational states. According to the Boltzmann distribution (which gives number of molecules present at different states of energy level) more molecules will occupy the lowest energy state (at ambient temperature). Thus at ambient temperature, due to decreased population of excited vibrational state, Stokes scattering is more intense than anti-Stokes scattering. Furthermore, with increase in temperature (increased population of excited vibrational state) the intensity of anti-Stokes scattering increases relative to Stokes scattering. The vibrational information is specific to the chemical bonds and symmetry of molecules, which act as a fingerprint of that particular molecule. Hence Raman spectroscopy is a powerful tool to probe the molecular bonds of a material. The Raman spectrum is typically plotted as the scattered light intensity as a function of the wavenumber difference between incident and scattered light, typically in cm-1 (which corresponds to difference between incident and scattered photon energy, 1 meV = 8.0655447 cm-1).9 73PDF Image | PRODUCTION AND APPLICATIONS OF GRAPHENE AND ITS COMPOSITES
PDF Search Title:
PRODUCTION AND APPLICATIONS OF GRAPHENE AND ITS COMPOSITESOriginal File Name Searched:
graphene-production-applications.PDFDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Power up your energy storage game with Salgenx Salt Water Battery. With its advanced technology, the flow battery provides reliable, scalable, and sustainable energy storage for utility-scale projects. Upgrade to a Salgenx flow battery today and take control of your energy future.
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |