The prototype of 
Bootis stars was found by Morgan et al. (1943)
and the group can be described as
metal-poor PopulationI, A-type stars with no magnetic field
larger than 
.
In a recent paper (Paunzen et al. 1997) we have reviewed the various
classification criteria
and have established a homogeneous group of 
Bootis stars.
Although 
Bootis stars occupy the same
parameter space in a Hertzsprung-Russell-diagramme as do "normal" A-type
and some peculiar (CP1, cool CP2) stars,
they are distinguished e.g. by results of high resolution spectroscopy
and UV observations.
The evolutionary status of 
Bootis stars is still controversial.
The two theories discussed in the literature
involve diffusion, either in combination with accretion of
interstellar matter as in post-AGB stars (Turcotte & Charbonneau 1993),
or with mass loss (Michaud & Charland 1986).
With the tools of asteroseismology it is in principle possible to investigate
the evolutionary status and internal structure of a star from its pulsation
frequency spectrum.
We therefore have started a photometric survey for pulsation
among 
Bootis stars in 1993. Eight observing runs were at least partly
dedicated to this survey so far (Table2 (click here)). Up to now we have found 13 new
pulsating members of this
group (Weiss et al. 1994; Paunzen & Handler 1996 and references therein).
Frequencies (6 to 45d
) and amplitudes suggest a close
connection to 
Scuti stars.
The main theoretical framework to describe 
Scuti pulsation
is well developed, although the effects of
diffusion and low metallicity on pulsation are not conclusively
investigated yet.
A comparison of the CP1 and 
Bootis stars is especially interesting.
For both groups, diffusion seems to be the main mechanism responsible
for the overabundance
(CP1) as well as for the underabundance of metals (
Bootis stars). However,
the first group
consists of typically nonvariable stars (Alecian 1996), which is
not the case for the second group.
Some preliminary null results of our survey have been published
in a series of IBVS-notes (Kuschnig et al. 1996; Paunzen et al. 1996a,b).
In this paper we present all data
on "constant" stars, in the sense that we are able to give an upper
limit for a possible variability. For each set of differential data
we have computed a Fourier spectrum (Figs. 4 (click here)a to 4 (click here)c).
Table 1: Observation log and results for the observed stars
Table 1: continued
