close
The essential knowledge of Raman Spectroscopy was taught in this laboratory session. Not only was the optical setup of a Raman Spectrometer presented to students, but the use of proprietary software for obtaining data was also described in the laboratory. The Raman Spectrum allows students to observe the vibrational energy of molecules. By identifying the molecular vibrations, the result showed Raman Scattering.
Both Raman spectroscopy and Infrared (IR) spectroscopy are used to study the vibrational energy of molecular motion. The difference between Raman spectroscopy and IR spectroscopy is that Raman spectroscopy is a scattering spectrum, and IR spectroscopy is the absorption of light rays. Although an IR instrument is cheaper than a Raman instrument, Raman spectroscopy has several advantages over IR spectroscopy. First of all, a transparent sample is not required in Raman spectroscopy, and a transparent sample is required in IR spectroscopy. Therefore, preparing a sample for Raman spectroscopy is easier than IR spectroscopy. Next, the laser is inconvenient to use in IR spectroscopy and needs a number of grating covers over the entire infrared region. The light source of Raman can be the laser, which is much more convenient. In general, the strong bands in the IR spectrum of a compound correspond to weak bands in the Raman and vice versa. This complimentary nature is due to the electrical characteristic of the vibration. If a bond is strongly polarized, a small change in its length, such as that occurs during a vibration, will have only a small additional effect on polarization.
Before using Raman spectroscopy, the definition of Raman scattering needs to be understood. Raman scattering occurs when the surface of a sample is not smooth. Due to the medium molecular vibrations or rotation, there is an energy exchange which occurs between the incident photon and the medium molecular transition. This change occurs such that the scattered light frequency reflects. Therefore, the frequency exchange between the incident and scattered light can be regarded as the energy exchange between the incident photon and scattering molecules. This is dependent on the structure of the medium itself, bonding, and vibrational levels. Other characteristics do not need to consider the frequency of the incident radiation.
Raman Scattering:
When the incident photons and molecules hit the surface, the electrons transit from a ground state to a virtual state. The molecules do not absorb the energy, but they release energy scattering. This released energy is exactly equal to the energy of the incident photons. The scattered light is called Rayleigh scattering.
Both Raman spectroscopy and Infrared (IR) spectroscopy are used to study the vibrational energy of molecular motion. The difference between Raman spectroscopy and IR spectroscopy is that Raman spectroscopy is a scattering spectrum, and IR spectroscopy is the absorption of light rays. Although an IR instrument is cheaper than a Raman instrument, Raman spectroscopy has several advantages over IR spectroscopy. First of all, a transparent sample is not required in Raman spectroscopy, and a transparent sample is required in IR spectroscopy. Therefore, preparing a sample for Raman spectroscopy is easier than IR spectroscopy. Next, the laser is inconvenient to use in IR spectroscopy and needs a number of grating covers over the entire infrared region. The light source of Raman can be the laser, which is much more convenient. In general, the strong bands in the IR spectrum of a compound correspond to weak bands in the Raman and vice versa. This complimentary nature is due to the electrical characteristic of the vibration. If a bond is strongly polarized, a small change in its length, such as that occurs during a vibration, will have only a small additional effect on polarization.
Before using Raman spectroscopy, the definition of Raman scattering needs to be understood. Raman scattering occurs when the surface of a sample is not smooth. Due to the medium molecular vibrations or rotation, there is an energy exchange which occurs between the incident photon and the medium molecular transition. This change occurs such that the scattered light frequency reflects. Therefore, the frequency exchange between the incident and scattered light can be regarded as the energy exchange between the incident photon and scattering molecules. This is dependent on the structure of the medium itself, bonding, and vibrational levels. Other characteristics do not need to consider the frequency of the incident radiation.
Raman Scattering:
When the incident photons and molecules hit the surface, the electrons transit from a ground state to a virtual state. The molecules do not absorb the energy, but they release energy scattering. This released energy is exactly equal to the energy of the incident photons. The scattered light is called Rayleigh scattering.
全站熱搜
留言列表
