Heidelberg 1999 – wissenschaftliches Programm
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MO: Molekülphysik
MO 11: Poster V: Theorie - Struktur und Dynamik
MO 11.2: Poster
Dienstag, 16. März 1999, 16:00–19:00, PA
MQDT analysis of np Rydberg states of rotationally and vibrationally excited H3 molecules. — •I. Mistrik1, R. Reichle1, M. Braun1, H. Helm1, U. Müller1, M. Jungen2, and J. Stephens3 — 1Fak. f. Physik, Univ. Freiburg, Stefan-Meier-Str.19, 79104 Freiburg — 2Institute of Physical chemistry, Univ. Basel, Klingelbergstrasse 80, 4056 Basel,Switzerland — 3International Atomic Energy Agency, Wagramer Strasse 5, Vienna, Austria A-1400
A recently measured two photon excitation spectrum of H3 np Rydberg
series[1]
converging to the (1,00) vibrationally excited H3+ ionic level has
been analysed.
A first photon excites the long-lived vibrationless metastable state
2pA2" (N=0,K=0)
to the vibrationally excited 3sA1′ (N=1,K=0)
intermediate state while the second photon populates autoionizing np
Rydberg
states below the N+=1 ionic limit (quasidiscrete spectrum), between the
N+=1 and
N+=3 limits (Beutler-Fano region) and above the N+=3 limit
(structured continuum).
Our MQDT[2] calculation, based on a highly accurate
Born-Oppenheimer potential energy surfaces of H3, predicts the
photoexcitation
cross-section to the np Rydberg states in these three spectral regions. The
rotational, vibrational and Jahn-Teller interactions between ionization
channels are explicitly included in this model. Numerous vibrational interlopers
with
low principal quantum number appear in the experimental spectrum and are
reproduced in the MQDT simulation, permitting
the tentative assignment of these states.
This work is supported by the DFG (SFB 276, TP C13).
[1] R. Reichle and I.Mistrik at al., (this conference)
[2] J. A. Stephens and H. Greene, J. Chem. Phys. 102(4), 1579 (1995)