Resonance characterization complex rotation method

To summarize, for our model Hamiltonian, resonances appear after a bound-virtual and a virtual-virtual resonance transition. There is no method to obtain virtual energies using a square-integrable basis set, even in the complex-rotated formalism. Then, at this point we can ask if FSS is a useful method to study this kind of resonance. As we will show in the next subsection, the answer is yes FSS is a method to obtain near-threshold properties, and with FSS we can characterize the near-threshold resonances by solving the Hermitian (not complex-rotated) Hamiltonian using a real square-integrable basis-set expansion. Moreover, the critical point of the virtual resonance-resonance transition, Xr, could also be obtained using FSS. 

Supersonic expansion cooling in the study of biomolecular systems thus results in a significant depopulation of excited rotational and vibrational levels, which decreases the spectral congestion dramatically. This allows one to characterize individual conformers - and their complexes - using double resonance spectroscopic techniques. These methods are described in Sects. 1.3.4—1.3.7. 

Solid-state nuclear magnetic resonance (NMR) has been extensively used to assess structural properties, electronic parameters and diffusion behavior of the hydride phases of numerous metals and alloys using mostly transient NMR techniques or low-resolution spectroscopy [3]. The NMR relaxation times are extremely useful to assess various diffusion processes over very wide ranges of hydrogen mobility in crystalline and amorphous phases [3]. In addition, several borohydrides [4-6] and alanates [7-11] have also been characterized by these conventional solid-state NMR methods over the years where most attention was on rotation dynamics of the BHT, A1H4, and AlHe anions detection of order-disorder phase transitions or thermal decomposition. There has been little indication of fast long-range diffusion behavior in any complex hydride studied by NMR to date [4-11]. 

---