avr - would using the reference voltage of an ADC as a VOLTAGE SOURCE affect my ADC or the stability of the circuit?

I am using an Arduino to capture an AC signal. However, the application is sensitive and needs a high resolution, I decided to use the internal 1.1 Volt as a voltage reference for the ADC.

In the case of using 5 volt as a voltage reference for the ADC :

The AC signal contains negative voltages which the Arduino can't capture ( the Arduino is capable of measuring 0-5 volts) so I used two resistors connected to the 5 volt from Arduino and then the ground of my signal is to be connected to the 2.5 volt.

(the upper left part of the picture).

And that worked fine

my question is, if I want to use the 1.1 Volt as a voltage source which is to be connected to the two resistors to provide .55V (1.1V /2) as a middle point for my AC instead of 2.5 volt, would connecting the VRef pin to the Resistors affect the ADC? will it make it unstable ?

Answer

From the ATmega328P datasheet:

Note that V_REF is a high impedance source, and only a capacitive load should be connected in a system.

You will need to use a voltage follower buffer in order to present a high impedance so that you disrupt the ADC as little as possible.