TY - JOUR
T1 - Vibrational dynamics of LiBH4by infrared pump-probe and 2D spectroscopy
AU - Andresen, Esben Ravn
AU - Gremaud, Robin
AU - Borgschulte, Andreas
AU - Ramirez-Cuesta, Anibal Javier
AU - Züttel, Andreas
AU - Hamm, Peter
PY - 2009/11/19
Y1 - 2009/11/19
N2 - Employing femtosecond IR pump-probe and 2D spectroscopy, we measure the vibrational dynamics of LiBH4 and several of its deuterium isotopomers. We find that the vibrational lifetime of various BH and BD stretching modes uniformly is »1.5 ps for all BH4-XD X- units (0 < x < 4). Subsequently, vibrational energy cascades down through BH and BD bending, facilitated by a strong Fermi resonance, into external (librational and translational) modes with a 3 ps time constant. Final thermalization of the energy is completed in about 100 ps. The vibrational spectra are purely homogeneously broadened indicating low inhomogeneity due to static disorder. We furthermore measured the anharmonic constants of various modes, which sets the benchmark for future ab initio calculations, and completed the first FTIR assignment of the stretching vibrations for the five BH4-xDx- units.
AB - Employing femtosecond IR pump-probe and 2D spectroscopy, we measure the vibrational dynamics of LiBH4 and several of its deuterium isotopomers. We find that the vibrational lifetime of various BH and BD stretching modes uniformly is »1.5 ps for all BH4-XD X- units (0 < x < 4). Subsequently, vibrational energy cascades down through BH and BD bending, facilitated by a strong Fermi resonance, into external (librational and translational) modes with a 3 ps time constant. Final thermalization of the energy is completed in about 100 ps. The vibrational spectra are purely homogeneously broadened indicating low inhomogeneity due to static disorder. We furthermore measured the anharmonic constants of various modes, which sets the benchmark for future ab initio calculations, and completed the first FTIR assignment of the stretching vibrations for the five BH4-xDx- units.
UR - http://www.scopus.com/inward/record.url?scp=70449567431&partnerID=8YFLogxK
U2 - 10.1021/jp907746z
DO - 10.1021/jp907746z
M3 - Article
AN - SCOPUS:70449567431
SN - 1089-5639
VL - 113
SP - 12838
EP - 12846
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 46
ER -