Molecular beam method

Sooies G (ed) 1988 Atomic and Molecular Beam Methods vo s 1 and 2 (New York Oxford University Press)... 

Bederson B and Dalgarno A (eds) 1994 Advances in Atomic Molecular and Optical Physics vol 32 Bederson B and Walther FI (eds) 1994 Advances in Atomic Molecular and Optical Physics vol 33 Bederson B and Walther FI (eds) 1998 Advances in Atomic Molecular and Optical Physics vol 38 Scoles G (ed) 1988 Atomic and Molecular Beam Methods (New York Oxford University Press)... 

The value of the magnetic hyperfine interaction constant C = 22.00 kHz is supposed to be reliably measured in the molecular beam method [71]. Experimental data for 15N2 are shown in Fig. 1.24, which depicts the density-dependence of T2 = (27tAv1/2)-1 at several temperatures. The fact that the dependences T2(p) are linear until 200 amagat proves that binary estimation of the rotational relaxation rate is valid within these limits and that Eq. (1.124) may be used to estimate cross-section oj from... 

Atomic and Molecular Beam Methods, G. Scoles (ed.), Oxford University Press, New York, 1988, vol. 1. 

When this surface is reacted with methanol, then methoxy is formed as demonstrated by a variety of techniques, including molecular beam methods [12], TPD [12,13], IRAS [14] and UPS [15]. Fig. 4a shows a layer of oxygen which has partially reacted and formed... 

Various reactions in which the reactants are in particular vibrational and rotational states have been investigated and state-to-state kinetics have been studied. Two procedures have been used in these investigations. Brooks and coworkers first employed the molecular beam method for studying the state-to-state kinetics. The reactants molecules are put into desired vibrational and rotational states by laser excitation and identified the states by their fluorescence. In molecular beam experiments, it is possible to control the translational energy and mutual orientation of the reactants and to determine the degree of polarization of the rotational angular momentum of the product. 

The molecular beam method has an advantage as compared to bulk method because translational energy can be controlled in the molecular beam method. However, in bulk method the reactant molecules can be formed in much wider range of vibrational and rotational states. 

It may finally be mentioned that molecular beam methods have been used for the preparation of semiconductors as GaP and of thin films of higher polyphosphides. 

Calibration of N cuum Gauges at Pressures below 10" mbar with a molecular beam method Vakuum-Technik, 30,1981,226-231... 

Neutral species are best sampled using molecular beam methods in which the neutral beam is modulated between the sampling orifice and the ionization chamber of the mass spectrometer and only the modulated component of the mass spectrometer output is recorded. This approach enables all neutral species, including radicals to be detected with a comparable sensitivity. If modulation techniques are not used, the sensitivity for detecting condensible or reactive species is much less than for non-condensible, non-reactive neutral molecules because of the much larger effective pumping speed for the former in the mass spectrometer chamber. However, the ease of installation of non-line-of-sight non-modulated... 

Harpoon reactions of alkaline metal atoms with halogen molecules in the gas phase seem to be the first instance of the observation of chemical electron transfer reactions at distances somewhat exceeding gas-kinetic diameters. Actually, as far back as 1932, Polanyi, while studying diffusion flames found for these reactions cross-sections of nR2, somewhat exceeding the gas-kinetic cross-sections [69]. Subsequently, more precise measurements which were carried out in the 1950s and 1960s with the help of the molecular beam method, confirmed the validity of this conclusion [70],... 

A given elementary reaction can be studied using molecular beam methods. It is found that reaction becomes faster as the vibrational ladder is climbed, i.e reaction... 

The two-route mechanism (1) was qualitatively substantiated by Winter-bottom [45], A system of steps corresponding to this mechanism was first given by Kuchaev and Nikitushina [46] who also studied a steady-state kinetic model. Rate constants for mechanism (1) were reported by Cassuto et al. [48, 49, 65,107,108]. All except k3 were determined using the molecular beam method. The value for k3 was obtained from the solution of the inverse problem. It is these constants that will be applied by us here. 

A very recent second example of a sudden change in A0f was found for the system N2-Ru(0 0 0 1) by Papageorgopoulos et al. [69]. N2 can dissociate on this surface, which is relevant for ammonia synthesis, see, e.g. [70,71]. The width A0f is plotted in Fig. 7. A trend very similar to that found for 02-Ag(l 1 1) is observed. Note the difference with Ar scattering in Figs 5 and 7. Clearly, the fast N2 sees a change of potential. In this case, this change in potential has been predicted and verified theoretically [70, 72]. The observation of this change for A0f and the connection to the shape of the interaction potential shows the power of the molecular beams method in the exploration of gas-surface dynamics. 

Scoles G., Bassi D., Buck U., Laine D., ed. Atomic and Molecular Beams Methods I. Oxford University Press Oxford, 1988, Vol. 1. 

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