 Hello, this is Professor Steven Neschva, and I'm here to help you out a little bit with using Spartan to determine some aspects of the intermolecular potentials. And so what I've done here is I've set up two chlorine molecules, and and they're currently in ball and spoke, but I think that for this purpose, it's going to be a little bit better to go into space filling mode. And well, one tool that I just want to alert you to is that you can tell the difference, the distance between these molecules by going to this distance icon, which you'll be able to go to if you don't want to make it a default icon like that, you can go to that geometry. But I'm going to go here. You click on one, you click on the other, and it reads out here that these are 33 0.8 angstroms apart. So that's pretty handy. Now, there's another handy icon here, which is this energy minimizer, which I'm going to just press it, and you notice that it's got a readout of 0 here, and what that means is that there's no interaction between these at all, and well, that's fine. On the other hand, what that probably means is that they're too far apart for them to see each other. So I'm going to do another command now. You probably know that just rotating all I do is use the mouse button for that. On the other hand, if I say control on the Mac, control, and then scroll, that just rotates one of them, which is kind of nice. And the same way is if I press command and move my mouse around, it moves the whole thing, but if I hit control command, then I can move just one of them. So that's that latter one is what I really want to do. I'm going to move by control command, I'm going to move them a little bit closer, and then I'm going to hit this energy minimizer to see if they start to see each other, and the answer is no. Okay, so I'm going to move in a little bit closer and see if they start to see each other. Still 0, move them a little bit closer, and still 0, and I'm going to move this one. A little bit closer, and oh, I think they just saw each other a little bit, and I'm going to move them in a little bit closer, and there's something really happened. So if I do an undo, which is command Z, I just brought them into within range, so now I'm going to measure the distance between them, and I see that it's about nine. So I conclude that the range of interactions between these two molecules is nine angstroms or less. So that's good to know, and the other thing that's good to know, I'm going to hit this minimizer again, which is makes it obvious that these guys have reoriented. So there's there's a reorientation that also has to do with this intermolecular attraction. Finally, you notice that this number is now minus 4.6, and you know, we can just round this up to the nearest kilojouple mole. So minus five. What that means, of course, is that to pull these apart, it would take about 4.6 kilojoules to pull them apart, because they've sort of fallen into a state in which the energy is minus 4.6. So getting from minus 4.6 back up to zero, that's the bond strength between, or the intermolecular bond strength between, between those two molecules. So that's one part of that. I also need to just remind, make sure I note that all this, these manipulations that we're talking about, you have to have this thing open that is to say, if you're in that view, then those special translation command keys don't work. So one other thing I just want to mention here, and it goes something like this, I'm going to just build a bunch of water molecules, and because maybe I'm interested in how water molecules interact, but now what I'm doing is I'm trying to create a cluster of them, and the reason for that is that I want to know how a whole bunch of them interact, and I'm going to do that. I just hit the molecular mechanics minimizer, and here we are. You can see that they're all interacting. Now, it is handy sometimes to turn on the model of hydrogen bonds. So I'm going to do that, and you can kind of see that there have been some hydrogen bonds forming here. And so that's just handy to notice, and and that's, so that's that. And then sort of the last thing I want you to, you know, be aware of is we can do the same thing, you know, if I imagine, for example, that this is liquid water, and so I'm just going to let it all do that, and I'm thinking maybe this molecule right here is at the surface of liquid. How much does it take, you know, for that molecule or this molecule to evaporate away from that? And the name for that is called the enthalpy of vaporization. It's not a perfect measure, but it does kind of give us a sense of a sense of the energy that's required for a water molecule to evaporate. So what I'm going to do is I'm going to choose this guy here, and then now I'm doing the control command to move it to the right. I can see I've broken those bonds. I'm going to move it way over here. Okay, and and now I'm going to look at the energy. So here we're going to have to do a little bit of a calculation. This looks like I needed to move it a little bit farther away. So here we go. I'm moving it way over here. So this energy that we're looking at here is the is the is the energy of that molecule connected to the surface. So I'm going to take that number here and subtract away the number when they're close together like that. And that would give me some sense of how much energy it takes to vaporize that molecule. I would say take the difference between that and this number now. Okay, I think that's it for now.