Probing spectral properties of radio-quiet quasars searched for optical
  microvariability-II
  In the context of AGN unification scheme rapid variability properties play an
important role in understanding any intrinsic differences between sources in
different classes. In this respect any clue based on spectral properties will
be very useful toward understanding the mechanisms responsible for the origin
of rapid small scale optical variations, or microvariability. Here we have
added spectra of 46 radio-quiet quasars (RQQSOs) and Seyfert 1 galaxies to
those of our previous sample of 37 such objects, all of which had been
previously searched for microvariability. We took new optical spectra of 33
objects and obtained 13 others from the literature. Their \hbeta and \mgii
emission lines were carefully fit to determine line widths (FWHM) as well as
equivalent widths (EW) due to the broad emission line components. The line
widths were used to estimate black hole masses and Eddington ratios, $\ell$.
Both EW and FWHM are anticorrelated with $\ell$. Nearly all trends were in
agreement with our previous work, although the tendency for sources exhibiting
microvariability to be of lower luminosity was not confirmed. Most importantly,
this whole sample of EW distributions provides no evidence for the hypothesis
that a weak jet component in the radio quiet AGNs is responsible for their
microvariability.
