[MOS] November 25, 2008

[Zina Queen]

Seminar on

Modern Optics and Spectroscopy


Toward pure electronic spectroscopy

Vladimir Petrovic, MIT

Tuesday, November 25, 2008


12:00 - 1:00 p.m.



When the electronic transition dipole moment among molecular Rydberg 
states is significantly larger than the permanent dipole moment of 
the ion core, interactions with an external electric field that 
change the quantum numbers for the Rydberg electron, but conserve the 
quantum numbers of the ion core, are dominant. Such same-n* 
Rydberg-Rydberg interactions can be observed in both the Stark effect 
and in transitions. We have characterized the Stark effect in Rydberg 
states of CaF, which has a Rydberg system of paradigmatic character 
with one of the largest dipole moments in a molecular ion, and which 
is among the molecules with the largest body of data available. The 
highly polar ion-core causes strong l-mixing, which distorts the 
expected patterns. Use of polarization diagnostics to assign the 
rotational quantum number, N, and the Stark effect to access and 
assign the N+ quantum number for higher-l states, provided 
information about the penetrative character of nominally 
core-nonpenetrating states, thus bridging our longrange and MQDT 
models. We are developing time domain THz and chirped-pulse microwave 
spectroscopic techniques for studying pure electronic spectra in 
transmission, which yield same information as in the Stark effect but 
without difficult detective work.  In addition, models that relate 
the observed transition intensities and mixing coefficients among 
different l series in pure electronic spectra will be discussed.


Grier Room, MIT Bldg 34-401
Refreshments served after the lecture
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