# First-order Properties
## Available Coupled Cluster Methods
- [`CCS`](./../general_sections/jobs.md#CCS)
- [`PE-CCS`](./../embedding_schemes/pe.md#how-to-include-pe)
- [`CC2`](./../general_sections/jobs.md#CC2)
- [`CCSD`](./../general_sections/jobs.md#CCSD)
- [`PE-CCSD`](./../embedding_schemes/pe.md#how-to-include-pe)
- [`CCSD(T)`](./../general_sections/jobs.md#CCSD(T))
- [`CC3`](./../general_sections/jobs.md#CC3)
- [`CCSDT`](./../general_sections/jobs.md#CCSDT)
- [`CCSDTQ`](./../general_sections/jobs.md#CCSDTQ)

## Available Cluster Perturbation Methods
- [`CPS(D)`](./../general_sections/jobs.md#CPS(D))
- [`CPSD(T)`](./../general_sections/jobs.md#CPSD(T))

## Example Input File
An example input file for CCS takes the following form:
```
@method settings
basis: STO-3G
@end

@memory
max_mem: 1
@end

@jobs
task: ccs
@end

@ccs
dipole: True
@end

@scf
conv_thresh: 1.0E-12
@end

@molecule
charge: 0
multiplicity: 1
units: bohr
xyz:
O        0.0000000000    0.0000000000    0.0000000000
H        0.0000000000    1.4304281903    1.1071565216
H        0.0000000000   -1.4304281903    1.1071565216
@end
```

## Relevant Keywords
| `dipole` <a id="dipole"></a> | |
|----------------|------------------------------------------------------------|
| **Description** | Calculate dipole moment. Gives the dipole moment in the length gauge. |
| **Type**        | bool |
| **Default**     | False |

<br>

| `relaxed` <a id="relaxed"></a> | |
|----------------|------------------------------------------------------------|
| **Description** | Include orbital relaxation in the dipole moment. |
| **Type**        | bool |
| **Default**     | False |
| **Availability**| [`CCSD`](./../general_sections/jobs.md#CCSD) |