Rotation alignment

Dressier R A, Meyer H and Leone S R 1987 Laser probing of the rotational alignment of N drifted in He J. Chem. Phys. 87 6029-39... 

Beauregard J N and Mayne H R 1993 The role of reaetant rotation and rotational alignment in the dissoeiative ehemisorption of hydrogen on Ni(IOO) Chem. Phys. Lett. 205 515... 

Williams, G.T. Morimoto, R.I. (1990). Maximal stress-induced transcription from the human hsp70 promoter requires interactions with the basal promoter elements independent of rotational alignment. Mol. Cell. Biol. 10, 3125-3136. 

Park SH, Das BB, De Angelis AA, Scrima M, Opella SJ (2010) Mechanically, magnetically, and rotationally aligned membrane proteins in phospholipid bilayers give equivalent angular constraints for NMR structure determination. J Phys Chem B 114 13995-14003... 

A typical application is the use of the (2 + 1) REMPI scheme for measuring the (v,./) distribution of H2 produced in associative desorption from a surface. When the laser is tuned to a spectroscopic transition between individual quantum states in the X -> E electronic band, resonant two-photon absorption populates the E state and this is subsequently ionized by absorption of another photon. The ion current is proportional to the number in the specific (v,./) quantum state in the ground electronic state that is involved in the spectroscopic transition. Tuning the laser to another spectroscopic feature probes another (v, J) state. Therefore, recording the ion current as the laser is scanned over the electronic band maps out the population distribution of H2(v, J) produced in the associative desorption. Ef of the (v, J) state can also often be simultaneously measured using field - free ion TOF or laser pump - probe TOF detection techniques. The (2 +1) REMPI scheme for detecting H2 is almost independent of the rotational alignment and orientation f(M) of molecules so that only relative populations of the internal states... 

Figure 3.16. Population distribution b0 (a) and rotational alignment b2/b0 (b) plotted vs. the internal energy. As in Figure 3.15, Boltzmann population distributions are linear in such plots. The different symbols correspond to different spin-orbit states of NO. From Ref. [170].

A key new element in the associative desorption experiments is the ability to probe different rotational states and rotational alignment. Assuming that the dominant effect of rotation is to make the thresholds dependent upon rotational state,... 

This paper is necessarily a very abbreviated survey, but we hope we have demonstrated by these few examples that Coriolis coupling and rotational alignment play an important part in high-spin structures of odd-odd nuclei. This can be true for nuclei near closed... 

Dubs, M., Briihlmann, U., and Huber, J.R. (1986). Sub-Doppler laser-induced fluorescence measurements of the velocity distribution and rotational alignment of NO photofragments, J. Chem. Phys. 84, 3106-3119. 

Schwartz-Lavi, D., Bar, I., and Rosenwaks, S. (1986). Rotational alignment and non-statistical A doublet population in NO following (CHs CONO photodissociation, Chem. Phys. Lett. 128, 123-126. 

The three-dimensional study of the photodesorption of CO from Cr203 confirmed the importance of including the angular coordinates in the simulations [124, 125]. The measured rotational alignment of the desorbing CO molecules could be reproduced qualitatively but quantitative discrepancies... 

PES is strongly dependent on the molecular bond orientation, there can even be an ntj dependence of diffraction. Miura et al. [74] have shown that this leads to a difference in the rotational alignment of molecules scattered on or off-specular. However, as for rotational inelasticity, there are problems in the comparison of theoretical and experimental diffraction probabilities. 

Mull et al. [64] observed the bimodal translational energy distribution of desorbed NO from Ni(0 01) and Kliiner et al. [19] interpret the bimodality by ab initio calculations of the excited-state PES. Thiel et al. [20] carried out ab initio calculations of three-dimensional PES and explain the rotational alignment by the coupling between the excited-state and the ground-state PES observed in CO desorption from Cr2O3(0 0 01). Although the results of the desorption from the oxide surfaces are described later, ab initio calculations for the excited-state PES can be carried out on the oxide surface. 

The polarisation of the CaCl (B) chemiluminescence from the reaction Ca (1D) + HC1 has been measured [379] to determine the rotational alignment of the CaCl product and indicates a highly polarised distribution of product angular momenta. This is similar to the reactions of alkali atoms with hydrogen halides. 

Laser optogalvanic effect used for detection of NJ and CO" t Rotational alignment of and CC CB S ) measured... 

CH3 REMPI transitions these changes will be caused by the alignment of CH3 rotation relative to photolysis laser polarization. Different branches will depend on the (N, K) levels of the CH3 rotation in different ways. For example, the P(2) line only sees (N, K) = (2,1), while R(2) sees (N, K) -(2,1) and (2,2) and S(2) sees K = 0,1, and 2 sublevels. From these, the A o N, K) and (04)(1V,K) rotational alignment parameters were obtained. 

Fluorescence from electronically excited fragments formed in collisions of rotor accelerated beams of metastable rare-gas atoms with Brj and BrCN has been measured and used to probe the mechanisms of the processes involved. Polarization of fluorescence from KBr B) and Brj, produced in the Kr( P2,o) + 2 system shows that rotational alignment perpendicular to the relative velocity vectors of the colliding partners is retained in both inelastic and reactive scattering processes. No such polarization is observed in the fluorescence of CN(5 Z ) formed in reaction (18), and this can be explained by a two-stage harpooning... 

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