### The anisotropy in BSE calculation

Posted:

**Tue Jan 23, 2024 3:36 am**Dear developers:

Currently, I would like to perform direction-specific BSE calculations in a two-dimensional system, just as done in Fig. 3d of the article

https://www.nature.com/articles/s41563-022-01285-3

However, I have a few questions below：

（1）In my GW calculations, I set
to calculate static screening in plane since my system is 2D. Then, in my BSE calculations,
was set to get the absorption spectra along the y direction. Is my process correct?

（2）When performing BSE calculations without considering anisotropy, I will set
which means calculating along the 45° direction in the xy plane. So, is it correct to set
if I want to perform BSE calculations when deviating 30 degrees along the x direction?

Best wishes,

Guo

Currently, I would like to perform direction-specific BSE calculations in a two-dimensional system, just as done in Fig. 3d of the article

https://www.nature.com/articles/s41563-022-01285-3

However, I have a few questions below：

（1）In my GW calculations, I set

Code: Select all

```
% LongDrXp
1.000000 | 1.000000 | 0.000000 |
```

Code: Select all

```
% BLongDir
0.000000 | 1.000000 | 0.000000 |
```

（2）When performing BSE calculations without considering anisotropy, I will set

Code: Select all

```
% BLongDir
1.000000 | 1.000000 | 0.000000 |
```

Code: Select all

```
% BLongDir
0.866 | 0.5 | 0.000000 |
```

Best wishes,

Guo