1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
.. _lrtddft2:
=========================================
Linear response TDDFT 2 - indexed version
=========================================
Ground state
============
The linear response TDDFT calculation needs a converged ground state
calculation with a set of unoccupied states. It is safer to use 'dav' or 'cg'
eigensolver instead of the default 'rmm-diis' eigensolver to converge
unoccupied states. However, 'dav' and 'cg' are often too expensive for large
systems. In this case, you should use 'rmm-diis' with tens or hundreds of
extra states in addition to the unoccupied states you wish to converge.
.. literalinclude:: r-methyl-oxirane.xyz
.. literalinclude:: Oxirane_lrtddft2_unocc.py
Calculating response matrix and spectrum
========================================
The next step is to calculate the response matrix:
.. literalinclude:: Oxirane_lrtddft2_lr.py
Note: Unfortunately, spin is not implemented yet. For now, use 'lrtddft'.
Restarting, recalculating and analyzing spectrum
================================================
.. literalinclude:: Oxirane_lrtddft2_lr2.py
Quick reference
===============
Parameters for LrCommunicators:
================ ================= =================== ========================================
keyword type default value description
================ ================= =================== ========================================
``world`` ``Communicator`` None parent communicator
(usually gpaw.mpi.world)
``dd_size`` `int`` None Number of domains for domain
decomposition
``eh_size`` `int`` None Number of groups for parallelization
over e-h -pairs
================ ================= =================== ========================================
Note: world.size = dd_size x eh_size
Parameters for LrTDDFT2:
==================== ================== =================== ========================================
keyword type default value description
==================== ================== =================== ========================================
``basefilename`` ``string`` Prefix for all files created by LRTDDFT2
(e.g. ``dir/lr``)
``gs_calc`` ``GPAW`` Ground-state calculator, which has been
loaded from a file with
communicator=lr_communicators
calculation
``fxc`` ``string`` None Exchange-correlation kernel
``min_occ`` ``int`` None Index of the first occupied state
(inclusive)
``max_occ`` ``int`` None Index of the last occupied state
(inclusive)
``min_unocc`` ``int`` None Index of the first unoccupied state
(inclusive)
``max_unocc`` ``int`` None Index of the last unoccupied state
(inclusive)
``max_energy_diff`` ``float`` None Maximum Kohn-Sham eigenenergy difference
``recalculate`` ``string`` None What should be recalculated. Usually
nothing.
``lr_communicators`` ``LrCommuncators`` None
``txt`` ``string`` None Output
==================== ================== =================== ========================================
|
