Biomolecules are innately flexible, and undergo large-amplitude motions that affect the surrounding solvation shell. Dynamical X-ray scattering provides direct insight into global shape changes that the biomolecule undergoes during folding (1 nm and up length scale). THz spectroscopy directly probes solvation and collective motions on a somewhat smaller length scale (0.3-1 nm). Infrared spectroscopy looks at the influence of such motions on localized vibrational modes (up to 0.5 nm length scale). Molecular dynamics simulations and models of vibrational energy flow within biomolecules complement such experimental studies by providing a molecular-level explanation for the experimental observations. In this review, we consider the interplay between simulation and experiment across length scales for biomolecules such as carbohydrates and globular proteins.

Contents	PAGE
1. Introduction	554
2. Experimental tools	556
2.1. Infrared spectroscopy	557
2.2. THz absorption spectroscopy	560
2.3. SAXS	561
3. Theoretical tools	564
3.1. Molecular dynamics simulations	565
3.2. Spectral density	565
3.3. Computational studies of energy flow	567
3.4. Hydrogen bond dynamics in solvation shells	568
3.5. The fractal nature of biomolecules	569
4. Two cases: carbohydrate solutions and protein folding/solvation \ dynamics	572
4.1. Carbohydrates	572
4.2. Proteins	575
5. Summary and outlook	579
Acknowledgments	580
References	580