Energy Transfer During Collisions

The internal energy ab+ is composed of the internal energy prior to the collision, FAB+, and of the amount of energy Q transferred during the collision  

the collision marks a restart of the time scale for the activated ion. As Q ab+ generally holds, the internal energy prior to the collision is of minor relevance - though not generally negligible - for the behavior of the activated ion. As may be expected, the CID spectra of stable molecular ions exhibit marked similarity to the 70-eV El spectra of the respective compounds [15,16]. 

Example Except for the intensities relative to the precursor ion, the B/E-linked scan CID spectrum of the toluene molecular ion, m/z 92, closely resembles the 70-eV El mass spectrum (Fig. 9.5 for El cf. Chap. 6.4.3). Here, all fragments are due 

For a polyatomic ion consisting both of the atom B actually, involved in the collision process, and the remainder A, the maximum of Q is calculated to have a lower value than Ec. Assuming central collisions we obtain [19]  

However, most collisions are not head-on , but occur at some angle 6. Increasing fftAB makes decrease, whereas larger is beneficial for energy 

---

The Franck-Hertz experiment and atomic energy levels Electrons can excite atoms from one quantum state to another by energy transferred during collisions. The threshold energy for excitation exactly matches the emission of light as the atom drops back down to the lower state, thus confirming the existence of quantized states and showing that they may be excited by either mechanical impact of electrons or absorption of photons. 

We say such a collision is elastic if no energy transfers during the collision between the gas particle and the mirror but if energy does transfer - and it usually does - we say the collision is inelastic. 

The energy transferred during an inelastic collision passes from the hot molecule of steam to the cooler mirror. This energy flows in this direction because the steam initially possessed more energy per molecule than the mirror as a consequence of its higher temperature. It is merely a manifestation of the minus-oneth law of thermodynamics, as discussed in Chapter 1. 

The temperature—Increasing the temperature normally increases the reaction rate since each species has a higher kinetic energy and the number of collisions is increased. This increases the chance that enough energy will be transferred during collisions to cause the reaction. 

Gas particles in constant motion collide with each other and with the walls of their container. The kinetic-molecular theory states that the pressure exerted by a gas is a result of collisions of the molecules against the walls of the container, as shown in Figure 7. The kinetic-molecular theory considers collisions of gas particles to be perfectly elastic that is, energy is completely transferred during collisions. The total energy of the system, however, remains constant. 

This relation (Landau Teller, 1936) demonstrates the adiabatic behavior of vibrational relaxation. Usually the Massey parameter at low gas temperatures is high for molecular vibration cox ox k which explains the adiabatic behavior and results in the exponentially slow vibrational energy transfer during the VT relaxation During the adiabatic collision, a molecule has enough time for mai vibrations and the oscillator can actually be considered stractureless, which explains such a low level of energy transfer. An exponentially slow adiabatic VT relaxation and intensive vibrational excitation by electron impact result in the unique role of vibrational excitation in plasma chemistry. Molectrlar vibrations for gases... 

The process we are interested in is the rotational energy transfer during the collision as well as the diffraction of the diatomic from the surface that exhibits a two-dimensional corrugation. Since the diffraction is a quantum effect, we treat the whole system classically except for the directions X and Y parallel to the surface. The separation of the total Hamiltonian into a classical and quantum part reads as follows ... 

Internal conversion is a non-radiative transition between two electronic states of the same spin multiplicity. In solution, this process is followed by a vibrational relaxation towards the lowest vibrational level of the final electronic state. The excess vibrational energy can be indeed transferred to the solvent during collisions of the excited molecule with the surrounding solvent molecules. 

---