Lauri Halonen
A deep understanding of localization of rovibrational energy requires a combination of experimental and theoretical research. The Helsinki group has worked on several laser techniques of gaseous molecular samples: laser intracavity photoacoustic [1], cavity ring-down [2], Fourier transform laser intracavity absorption [3] and laser-induced dispersive rovibrational spectroscopy [4]. The last one mentioned has been developed by the Helsinki group and yields new type of molecular information on rovibrational energy localization. The latest developments include a tight lock of a high-resolution laser to high-finesse cavity (Pound-Drewer-Hall locking). The Helsinki theory work includes forming molecular kinetic energy operators to describe the states excited by our laser experiments. Particularly the branch of mathematics called geometric algebra has been found to be successful [5,6]. These tools with state-of-the art electronic structure calculations (use of the R12 and high-order coupled cluster methods) for potential energy surfaces have been applied to ammonia-type molecules [7-10].
References
1. X. Zhan, E. Kauppi and L. Halonen, Rev. Scient. Instr., 63, 5546 (1992).
2. M. Metsala, S. Yang, O. Vaittinen, D. Permogorov and L. Halonen, Chem. Phys. Letters, 346, 373 (2001).
3. S. Yang, M. Metsala, T. Lantta, P. Suero, R. Martinez, O. Vaittinen and L. Halonen, Chem. Phys. Letters, submitted for publication.
4. M. Metsala, S. Yang, O. Vaittinen and L. Halonen, J. Chem. Phys., 117, 8686 (2002).
5. J. Pesonen, J. Chem. Phys., 114, 10598 (2001).
6. J. Pesonen and L. Halonen, Adv. Chem. Phys., 125, 269 (2003).
7. T. Rajamaki, A. Miani and L. Halonen, J. Chem. Phys., 118, 6358 (2003).
8. T. Rajamaki, A. Miani and L. Halonen, J. Chem. Phys., 118, 10929 (2003).
9. T. Rajamaki, J. Noga, P. Valiron and L. Halonen, Mol. Phys., accepted for publication.
10. T. Rajamaki, M. Kallay, J. Noga, P. Valiron and L. Halonen, Mol. Phys., accepted for publication.