Excitation photon energy

In the case of polyenes, the term I scattering is dominant in the Raman spectra resonant with the 1 flu excited states22,26 the contribution of the term m scattering is important in the Raman spectra resonant with the 2 Ag excited states27. In addition, an interference effect between the 1 flu and 2 kg states in a Raman-intensity vs excitation-photon-energy plot (which is called an excitation profile) of the in-phase C=C stretch has been suggested28. 

Laser irradiation onto the insulating (EDO)2PF6 crystal induces a phase transition to the highly conductive state within a few picoseconds [162, 180]. The crystal surface was excited by laser irradiation with a pulse width of 0.12 ps. The excitation photon energy (1.55 eV) was nearly resonant to the CT band at 11.1 x 10 cm (1.37 eV), directly reflecting the excitation of the charge ordered state. 

The first factor will dictate, from the properties of the one-electron wavefunctions, the characteristic dependence of the cross-sections on the initial orbital character of the electron and on the exciting photon energy. 

Evaluation of the Oni s requires detailed atomic calculations, with a good knowledge of the one-electron wavefunctions (the best results, especially for high 1 orbitals, are obtained by relativistic calculations). They are usually expressed as a function of the exciting photon energy hv. 

By carefully tuning the excitation photon energy, we can use XES to selectively observe the occupied electronic states projected on the oxygen atom of, respectively,... 

First attempts to investigate the photodissociation dynamics of Fe(CO)5 used molecular beam technology coupled with high intensity femptosecond lasers [47, 48]. It is important to note that these experiments relied on multiphoton absorption to populate the electronic excited states of Fe(CO)5. This work built on the results of earlier experiments using nanosecond pulsed lasers which provided information on the photoproduct distribution and their energies [37-40, 49-56]. The energies of the various dissociation processes for Fe(CO)5 are presented in Fig. 18 for comparison with the excitation photon energies and the absorption profile of Fe(CO)5. 

Figure 14. Dependence upon excitation photon energy hv of electron injection quantum yield 4>i obtained for various oxide semiconductors sensitized by cw-[Ru dcbpy)2(NCS)2].

Two-photon photoemission spectroscopy is known for its capability to reveal not only occupied but also unoccupied electronic density of states [10]. In this scheme, one photon excites an electron below the Fermi level to an intermediate state. A second photon then excites the electron from the intermediate state to a final state above the vacuum le vel. The photoelectron yields are strongly enhanced if the excitation photon energy is tuned to the resonance conditions, and the photoelectron spectrum reflects the electron lifetime in the intermediate states as well as their density of states. It is necessary to keep the employed photon energy below the work function of the sample, otherwise one photon photoemission signal becomes excessive and buries the 2PPE signals. 

Fig. 3.23 Photoluminescence (PL) spectra of differently doped samples at T = 10 K. The excitation photon energy is 3.1 eV Reprinted from [83], copyright 1996, with permission from Elsevier...

FIGURE 14. Dependence of the converted fraction (O) on the exciting photon energy (closed circles) for the phase transitions. Open circles and dashed lines show the action spectra of photoconductivity. Reproduced by permission of the American Physical Society... 

Figure 7.24. The PL-enhancing polaron resonance in PDPEA (see Figure 7.2) excited at = 353, 308, and 250 nm. Note that the amplitude of the resonance moderately decreases with increasing excitation photon energy (60],...

V. Gulbinas, Y. Zaushitsyn, H. Bassler, A. Yartsev, and V. Sundstrbm, Dynamics of charge pair generation in ladder-type poly(para-phenylene) at different excitation photon energies, Phys. Rev. B, 70, 035215 (2004). 

Furthermore, the term ri(Eo) accounts for ionization in all the atomic shells of the ith element where the electron-binding energy is less than the excitation photon energy Eo- Typically it is only the x-rays caused by electron transitions to one of the shells that is monitored in the fluorescence spectrometer. For example, it will be assumed that only the K x-rays of element i are being measured. In this case the number of ionizations of the K shell is reduced to... 

Fig.5.3-ft (a) Low-temperature (10 K) absorption spectra of CdSe dots dispersed in a polymer matrix, for various mean diameters. (b) Nanosecond saturated-absorption spectra for 67 A dots. The pump beam had a 7 ns FWHM. The excitation photon energy, 1.984 eV, is prolonged as a dashed vertical line from (a) for easier comparison. The horizontal dashed line corresponds to AOD = 0. (c),(d) Photoluminescence(PL) and photoluminescence-excitation(PLE, observed at 2.022 eV) spectra for 67 A dots (c) and for 62 A dots (d). (After [3.29])... 

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