The Look at atoms animation makes the camera continuously look at the atoms that were selected when the animation was created. Only the camera target moves while the camera position does not change.
This animation can be useful, for example, when you want to keep looking at some part of a system while animating its trajectory without changing the camera position.
See also: Follow atoms animation
Adding the animation
First, select atoms that you want the camera to look at and orient the view/camera as you would like it to be positioned.
Then, choose the start frame in the Animator's Track view and double-click on the Look at atoms animation effect in the Animation panel of the Animator.
The camera target point between the two keyframes will move with the geometric center of the specified atoms. The current camera position is used for the start and end frames.
Set the end frame of the animation as needed.
Note: You can always move the start and end frames of the animation.
Properties
By default, camera animations are applied to the active camera (to change that, inspect the animation and modify the "Apply to active camera" option). So, the target point of the animation will be defined as the current target position of the active camera, which is basically the current center of the view.
The camera positions might be defined differently whether you have the grid in the viewport switched on or off. To change how the animation behaves depending on whether the grid is on or off, inspect the animation and modify the "Keep camera upwards" option - if this option is checked then it will depend on whether the grid is on or off.
Adjusting camera positions
You can adjust the camera position using the animation controllers but the camera target is kept at the geometric center of the specified atoms. See Adjusting camera positions.