Abstract
The formation of protonated and unprotonated ammonia cluster ions is studied by femtosecond two colour two photon pump-probe techniques applied to (NH3) n and (ND3) n clusters withn up to 8. The fourth harmonic (∼ 200 nm, 6.2 eV, 160 fs) of a Ti: Sapphire laser pulse is used to excite the clusters in a state corresponding to theà state of NH3 while the third harmonic (267 nm, 4.65 eV) is used for the subsequent ionisation step. Employing a combination of the optical Bloch equations for the excitation process and rate equations for the cluster dynamics we calibrate the zero time delay and carefully analyse the time dependence of the pump-probe signal. Several distinct intermediate steps in the time evolution can be distinguished, having characteristic time constants ranging from 40 fs to over 100 ps. They are discussed in a consistent scheme for the excitation, ionisation and protonation dynamics, accounting also for characteristic differences observed between deuterated and undeuterated species. A particularly remarkable time dependence of the homogeneous (NH3) +2 cluster ion signal is interpreted as a fingerprint of internally protonated neutral precursors of the type NH3NH2NH4.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Greer, J.C., Ahlrichs, R., Hertel, I.V.: Chem. Phys.133, 191 (1989)
Greer, J.C., Ahlrichs, R., Hertel, I.V.: Z. Phys. D18, 413 (1991)
Searles, S.K., Kebarle, P.: J. Phys. Chem.72, 742 (1968); Arshadi, M.R., Futrell, J.H.: J. Phys. Chem.78, 1482 (1974); Tan, I.N., Castleman, A.W.: J. Phys.62, 4576 (1975); Tan, I.N., Castleman, A.W.: J. Phys.62, 4576 (1975)
Ceyer, S.T., Tiedemann, P.W., Mahan, B.H., Lee, Y.T.L.: J. Chem. Phys.70, 14 (1979)
Echt, O., Dao, P.D., Morgan, S., Castleman Jr., A.W.: J. Chem. Phys.82, 4076 (1985)
Shinohara, H., Nishi, N., Washida, N.: J. Chem. Phys.83, 1939 (1985)
Kamke, W., Herrmann, R., Wang, Z., Hertel, I.V.: Z. Phys. D10, 491 (1988)
Kaiser, E., Vries, de J., Steger, H., Menzel, C., Kamke, W., Hertel I.V.: Z. Phys. D20, 193 (1991)
Misaizu, F., Houston, P.L., Nishi, N., Shinohara, H., Kondow, T., Kinoshita, M.: J. Phys. Chem.93, 7041 (1989); Stephan, K., Märk, T.D., Futrell, J.H., Castleman Jr., A.W.: Vacuum33, 77 (1983); Buck, U., Meyer, H., Nelson Jr., D., Fraser, G., Klemperer, W.: J. Chem. Phys.88, 3028 (1988); Lifshitz, C., Louage, F.: J. Phys. Chem.93, 5633 (1989); Buck, U., Lauenstein, Ch.: J. Chem. Phys.92, 4250 (1990)
For a discussion of the nature of the bonding in neutral ammonia clusters see e.g. [1] and Greer, J.C., Ahlrichs, R., Hertel, I.V.: J. Chem. Phys.95, 3861 (1991)
Wei, S., Purnell, J., Buzza, S.A., Stanley, R.J., Castleman Jr., A.W.: J. Chem. Phys.97, 9480 (1992)
Purnell, J., Wei, S., Buzza, S.A., Castleman Jr., A.W.: J. Phys. Chem.97, 12530 (1993)
Buzza, S.A., Wei, S., Purnell J., Castleman Jr., A.W.: J. Chem. Phys.102, 4832 (1994)
Ziegler, L.D.: J. Chem. Phys.82, 664 (1985)
Vaida, V., McCarthy, M.I., Engelking, P.C., Rosmos, P., Werner, H.J., Botschwina, P.: J. Chem. Phys.86, 6669 (1987)
Ringling, J., Kittelmann, O., Noack, F., Korn, G., Squier, J.: Opt. Lett.18, 2035 (1993)
Fuke, K., Takasu, R., Misaizu, F.: Chem. Phys. Lett.229, 597 (1994)
Cheng, P.Y., Zhong, D., Zewail, A.H.: Chem. Phys. Lett.237, 399 (1995)
Hertel, T., Knoesel, E., Wolf, M., Ertl, G.: Phys. Rev. Lett. (submitted July 1995)
Loudon, R.: The quantum theory of light. New York: Oxford Univ. Press 1983
Harshbarger, W.R.: J. Chem. Phys.53, 903 (1970)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Freudenberg, T., Radloff, W., Ritze, H.H. et al. Ultrafast fragmentation and ionisation dynamics of ammonia clusters. Z Phys D - Atoms, Molecules and Clusters 36, 349–364 (1996). https://doi.org/10.1007/BF01426421
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01426421