title: Transverse acoustic modes of biogenic and alpha,omega-polyamines: a study by inelastic neutron scattering and Raman spectroscopies coupled to DFT calculations.
abstract: A complete analysis of the transverse acoustic modes (TAMs) for the homologous series of alpha,omega-diamines (H2N(CH2)nNH2) (n = 2-10, n = 12) as well as for the biogenic polyamines spermidine and spermine was undertaken, by Raman and inelastic neutron scattering (INS) spectroscopies combined with density functional theory (DFT) calculations. A complete assignment of the whole set of TAMs was carried out, for both the undeuterated and N-deuterated species. 1,2-Diaminoethane was found to display exceptional behavior, probably due to the formation of dimers in the solid state. An n-even/n-odd dependence of the low frequency INS pattern was observed for these polyamines. The very good accordance between their INS experimental TAMs and the ones previously reported for the corresponding n-alkanes suggest a close conformational similarity between these systems.
authors.affiliation: Research Unit "Molecular Physical-Chemistry", University of Coimbra, 3000-401 Coimbra, Portugal.
authors.forename: Luís A E
authors.initials: LA
authors.lastname: Batista de Carvalho
authors.forename: M Paula M
authors.initials: MP
authors.lastname: Marques
authors.forename: John
authors.initials: J
authors.lastname: Tomkinson
mesh_terms: D000465:Algorithms; D015317:Biogenic Polyamines / Q000737:chemistry*; D015394:Molecular Structure; D033363:Neutron Diffraction; D011073:Polyamines / Q000737:chemistry*; D011789:Quantum Theory; D013059:Spectrum Analysis, Raman; D013095:Spermidine / Q000737:chemistry*; D013096:Spermine / Q000737:chemistry*
chemical_list: D015317:Biogenic Polyamines; D011073:Polyamines; D013096:Spermine; D013095:Spermidine