There are a number of ways you can create an infrared looking image in Photoshop. This is just one and it actually uses an R72 filter from Hoya. There are others but this is the filter I chose to use. You can turn a colour image into a B&W IR using the colour sliders and converting the image to monocrome but I prefer this method.
1. Take the photo with the Hoya R72 filter. You will need to compose your image before adding the filter to the lens. You'll see why if you try to do it with the filter on the lens.
Note: I have found the best way to focus is to use hyperfocal focusing. I focus with the lens in manual focus mode. Then before fitting the filter, switch it to auto focus. Why? because the autofocus mechanism prevents the lens moving when you fit the filter. Once you have the filter fitted, switch back to manual and be careful not to touch the focus ring.
Note 2: You will need to experiment with the exposure time. Most of my times are based on whatever the camera thought best, and then bracketed either side by a stop. I typically use AV mode and start with F16 working from there.
2. Open the image in photoshop.. it should look very purple/red (because you've caught mainly IR light)
3. Select "Auto Color" from the Image | Adjustments menu
4. Select "Channel Mixer" from the Image | Adjustments menu and change the Red channel to:
Red = 0
Blue = +100
5. Select "Channel Mixer again and set the Blue channel to:
Red = +100
Blue = 0
6. You can skip the previous step if you'd like a bit more colour in your image, see example below.
Or you can try this method:
1. Duplicate the background layer
2. Invert the duplicate (ctrl + i or command + i)
3. Set blend mode to colour
4. Adjust the opacity level to suit.