I have been having some “stubborn” imaginary frequencies when I calculate the S1 state of my molecule, 4 benzoylbenzoic acid (both in anion and cation), with a single water molecule. I am also having this issue when I attempt to run the S1 without water molecules.
Below is my input file for the geometric optimization of the anion of my molecule with one water molecule.
$rem
JOBTYPE opt
EXCHANGE B3LYP
BASIS aug-cc-pVDZ
CIS_N_ROOTS 5
CIS_STATE_DERIV 1
GEOM_OPT_TOL_GRADIENT 2
GEOM_OPT_TOL_ENERGY 1
GEOM_OPT_COORDS 0
DFT_D D3_BJ
MAX_SCF_CYCLES 1000
GEOM_OPT_MAX_CYCLES 1000
$end
$molecule
-1 1
C -0.3491237556 -0.7860532340 0.0221422394
C -1.7214073250 -1.4378118231 0.0508756605
C -0.0233913926 0.2942623793 -0.8100347805
C 0.6778157801 -1.3577195366 0.7890441415
C 2.2835640217 0.2313257368 -0.0782579110
C 1.2771411251 0.8016609061 -0.8617021538
C 1.9769239518 -0.8559119329 0.7494722229
C 3.6634768884 0.7612492715 -0.1361074728
H -0.7953850132 0.7390938565 -1.4343174220
H 0.4420451259 -2.2270898964 1.3996185041
H 1.5056444773 1.6405449909 -1.5171966475
H 2.7549993904 -1.3193787298 1.3539454856
C -2.9153908090 -0.6459695242 0.1496428247
C -4.1900550019 -1.3060458474 0.0626356143
H -4.1896343328 -2.3828129429 -0.0948684258
C -5.3768930232 -0.6017456442 0.1723777934
H -6.3245882509 -1.1402787708 0.0911391210
C -5.3874271870 0.7934541211 0.3878320262
H -6.3249098589 1.3419971320 0.4744002334
C -4.1445972092 1.4564839409 0.5019068524
H -4.1224187460 2.5318364375 0.6925611422
C -2.9472999143 0.7680350152 0.3879938531
H -2.0163788611 1.3175661471 0.5105367091
O -1.7258564536 -2.7032493434 -0.0075427416
O 4.6130666339 0.3997375480 0.6208503022
O 4.0708287048 1.6430141274 -0.9477323217
H 7.1301225485 1.7346853361 0.0047131882
O 6.9865961076 2.3431995342 -0.7294886152
H 6.0425886580 2.2224766457 -0.9167047005
$end
This is followed by a frequency calculation:
$rem
JOBTYPE freq
EXCHANGE B3LYP
BASIS aug-cc-pVDZ
DFT_D D3_BJ
MAX_SCF_CYCLES 1000
GEOM_OPT_MAX_CYCLES 1000
MEM_TOTAL 40192
CIS_N_ROOTS 1
CIS_STATE_DERIV 1
$end
$molecule
-1 1
C -0.3491237556 -0.7860532340 0.0221422394
C -1.7214073250 -1.4378118231 0.0508756605
C -0.0233913926 0.2942623793 -0.8100347805
C 0.6778157801 -1.3577195366 0.7890441415
C 2.2835640217 0.2313257368 -0.0782579110
C 1.2771411251 0.8016609061 -0.8617021538
C 1.9769239518 -0.8559119329 0.7494722229
C 3.6634768884 0.7612492715 -0.1361074728
H -0.7953850132 0.7390938565 -1.4343174220
H 0.4420451259 -2.2270898964 1.3996185041
H 1.5056444773 1.6405449909 -1.5171966475
H 2.7549993904 -1.3193787298 1.3539454856
C -2.9153908090 -0.6459695242 0.1496428247
C -4.1900550019 -1.3060458474 0.0626356143
H -4.1896343328 -2.3828129429 -0.0948684258
C -5.3768930232 -0.6017456442 0.1723777934
H -6.3245882509 -1.1402787708 0.0911391210
C -5.3874271870 0.7934541211 0.3878320262
H -6.3249098589 1.3419971320 0.4744002334
C -4.1445972092 1.4564839409 0.5019068524
H -4.1224187460 2.5318364375 0.6925611422
C -2.9472999143 0.7680350152 0.3879938531
H -2.0163788611 1.3175661471 0.5105367091
O -1.7258564536 -2.7032493434 -0.0075427416
O 4.6130666339 0.3997375480 0.6208503022
O 4.0708287048 1.6430141274 -0.9477323217
H 7.1301225485 1.7346853361 0.0047131882
O 6.9865961076 2.3431995342 -0.7294886152
H 6.0425886580 2.2224766457 -0.9167047005
$end
Here is the output for the frequency:
STANDARD THERMODYNAMIC QUANTITIES AT 298.15 K AND 1.00 ATM
This Molecule has 2 Imaginary Frequencies
Zero point vibrational energy: 135.615 kcal/mol
Atom 1 Element C Has Mass 12.00000
Atom 2 Element C Has Mass 12.00000
Atom 3 Element C Has Mass 12.00000
Atom 4 Element C Has Mass 12.00000
Atom 5 Element C Has Mass 12.00000
Atom 6 Element C Has Mass 12.00000
Atom 7 Element C Has Mass 12.00000
Atom 8 Element C Has Mass 12.00000
Atom 9 Element H Has Mass 1.00783
Atom 10 Element H Has Mass 1.00783
Atom 11 Element H Has Mass 1.00783
Atom 12 Element H Has Mass 1.00783
Atom 13 Element C Has Mass 12.00000
Atom 14 Element C Has Mass 12.00000
Atom 15 Element H Has Mass 1.00783
Atom 16 Element C Has Mass 12.00000
Atom 17 Element H Has Mass 1.00783
Atom 18 Element C Has Mass 12.00000
Atom 19 Element H Has Mass 1.00783
Atom 20 Element C Has Mass 12.00000
Atom 21 Element H Has Mass 1.00783
Atom 22 Element C Has Mass 12.00000
Atom 23 Element H Has Mass 1.00783
Atom 24 Element O Has Mass 15.99491
Atom 25 Element O Has Mass 15.99491
Atom 26 Element O Has Mass 15.99491
Atom 27 Element H Has Mass 1.00783
Atom 28 Element O Has Mass 15.99491
Atom 29 Element H Has Mass 1.00783
Molecular Mass: 243.065770 amu
Principal axes and moments of inertia in amu*Bohr^2:
1 2 3
Eigenvalues – 1459.51480 12375.80585 13411.39786
X 0.99999 -0.00410 -0.00002
Y 0.00410 0.99996 -0.00792
Z 0.00005 0.00792 0.99997
Rotational Symmetry Number is 1
The Molecule is an Asymmetric Top
Translational Enthalpy: 0.889 kcal/mol
Rotational Enthalpy: 0.889 kcal/mol
Vibrational Enthalpy: 143.167 kcal/mol
gas constant (RT): 0.592 kcal/mol
Translational Entropy: 42.365 cal/mol.K
Rotational Entropy: 33.848 cal/mol.K
Vibrational Entropy: 47.334 cal/mol.K
Total Enthalpy: 145.537 kcal/mol
Total Entropy: 123.547 cal/mol.K
I have also performed a frequency calculation, followed by an optimization, followed by a frequency calculation, as per a previous thread’s suggestion, and I still have 2 imaginary frequencies remaining.
This is the same case for the cation of the molecule with no water molecules.
Here is its input for the geometric optimization:
$rem
JOBTYPE opt
EXCHANGE B3LYP
BASIS aug-cc-pVDZ
CIS_N_ROOTS 1
CIS_STATE_DERIV 1
CIS_SINGLETS true
CIS_TRIPLETS false
GEOM_OPT_TOL_GRADIENT 1
GEOM_OPT_TOL_ENERGY 1
GEOM_OPT_COORDS 0
DFT_D D3_BJ
MAX_SCF_CYCLES 1000
GEOM_OPT_MAX_CYCLES 1000
$end
$molecule
1 1
O 4.5977638003 -1.7522985003 0.4409784025
O 5.2616544645 0.1770700267 -0.2379952613
C 0.1794243696 0.6476593676 0.0355001860
C -1.2041065465 1.0823181729 0.0506300760
C 0.5542137812 -0.6605267891 0.4270053310
C 1.1967816741 1.5678315258 -0.3175741969
C 2.8777197009 -0.1235985445 0.0598989639
C 1.8853672671 -1.0479444708 0.4362570543
C 2.5293168926 1.1887007385 -0.3121174445
C 4.2654586556 -0.5297204120 0.0739079985
H -0.2014358960 -1.3651554454 0.7617201876
H 0.9281733174 2.5807202549 -0.6026872715
H 2.1486305849 -2.0550249350 0.7511369106
H 3.2894812061 1.9133625444 -0.5971914437
H 5.5625350722 -1.9090188721 0.4131359516
C -2.3719747819 0.2436179622 0.0213726321
C -3.5876987799 0.6974848294 0.5971067524
H -3.6162396747 1.6340356702 1.1549252431
C -4.7379448038 -0.0797754310 0.5298821958
H -5.6558508604 0.2741458947 0.9972535529
C -4.7152096201 -1.3194077568 -0.1209048109
H -5.6191255171 -1.9244066890 -0.1740045448
C -3.5270703473 -1.7767301122 -0.7065464613
H -3.5129928471 -2.7286252293 -1.2355255820
C -2.3693067335 -1.0124907262 -0.6384304827
H -1.4700940503 -1.3555592799 -1.1443084436
O -1.3445795935 2.4205342512 0.1203492669
H -2.2647309170 2.6761816541 -0.0419024235
$end
And the frequency calculation:
$rem
JOBTYPE freq
EXCHANGE B3LYP
BASIS aug-cc-pVDZ
DFT_D D3_BJ
MAX_SCF_CYCLES 1000
GEOM_OPT_MAX_CYCLES 1000
MEM_TOTAL 20192
CIS_N_ROOTS 1
CIS_SINGLETS true
CIS_TRIPLETS false
CIS_STATE_DERIV 1
$end
$molecule
1 1
O 4.3855450224 -1.9704538430 1.0615646862
O 5.2154627365 -0.0555825754 0.5429722892
C 0.1662553068 0.6349592645 0.1427860863
C -1.1887120772 1.1283204800 -0.0168299508
C 0.4309055651 -0.7000296784 0.5317240766
C 1.2577767537 1.5203120230 -0.0313810970
C 2.8023696147 -0.2547550180 0.5090383806
C 1.7317099882 -1.1457049219 0.7102948860
C 2.5610394769 1.0827202206 0.1426147259
C 4.1574674374 -0.7239925349 0.6954720792
H -0.3900538166 -1.3819292048 0.7334796106
H 1.0707040475 2.5532063326 -0.3103905806
H 1.9088009283 -2.1737075345 1.0178451240
H 3.3812095507 1.7819791771 -0.0074772805
H 5.3378393878 -2.1708516653 1.1567752772
C -2.3653229399 0.3429806732 -0.2708170113
C -3.6407749748 0.8170197780 0.1348392226
H -3.7250310135 1.7231196048 0.7358667052
C -4.7918063780 0.0950696617 -0.1579224148
H -5.7597555395 0.4621526937 0.1806039622
C -4.7079450075 -1.1069262638 -0.8712940828
H -5.6119483598 -1.6685435977 -1.1024979889
C -3.4581889651 -1.5833986025 -1.2897856614
H -3.3936343819 -2.5055465121 -1.8657329428
C -2.3003206125 -0.8754819220 -0.9951007394
H -1.3445396250 -1.2302140115 -1.3728190178
O -1.2912688784 2.4658170037 0.1102192697
H -2.1685206663 2.7677448345 -0.1683518747
$end
Which has the same result of 2 imaginary frequencies:
STANDARD THERMODYNAMIC QUANTITIES AT 298.15 K AND 1.00 ATM
This Molecule has 2 Imaginary Frequencies
Zero point vibrational energy: 134.928 kcal/mol
Atom 1 Element O Has Mass 15.99491
Atom 2 Element O Has Mass 15.99491
Atom 3 Element C Has Mass 12.00000
Atom 4 Element C Has Mass 12.00000
Atom 5 Element C Has Mass 12.00000
Atom 6 Element C Has Mass 12.00000
Atom 7 Element C Has Mass 12.00000
Atom 8 Element C Has Mass 12.00000
Atom 9 Element C Has Mass 12.00000
Atom 10 Element C Has Mass 12.00000
Atom 11 Element H Has Mass 1.00783
Atom 12 Element H Has Mass 1.00783
Atom 13 Element H Has Mass 1.00783
Atom 14 Element H Has Mass 1.00783
Atom 15 Element H Has Mass 1.00783
Atom 16 Element C Has Mass 12.00000
Atom 17 Element C Has Mass 12.00000
Atom 18 Element H Has Mass 1.00783
Atom 19 Element C Has Mass 12.00000
Atom 20 Element H Has Mass 1.00783
Atom 21 Element C Has Mass 12.00000
Atom 22 Element H Has Mass 1.00783
Atom 23 Element C Has Mass 12.00000
Atom 24 Element H Has Mass 1.00783
Atom 25 Element C Has Mass 12.00000
Atom 26 Element H Has Mass 1.00783
Atom 27 Element O Has Mass 15.99491
Atom 28 Element H Has Mass 1.00783
Molecular Mass: 227.070860 amu
Principal axes and moments of inertia in amu*Bohr^2:
1 2 3
Eigenvalues – 1387.93310 8715.04896 9826.65545
X 1.00000 0.00196 -0.00062
Y -0.00196 1.00000 0.00208
Z 0.00063 -0.00208 1.00000
Rotational Symmetry Number is 1
The Molecule is an Asymmetric Top
Translational Enthalpy: 0.889 kcal/mol
Rotational Enthalpy: 0.889 kcal/mol
Vibrational Enthalpy: 141.044 kcal/mol
gas constant (RT): 0.592 kcal/mol
Translational Entropy: 42.162 cal/mol.K
Rotational Entropy: 33.141 cal/mol.K
Vibrational Entropy: 37.144 cal/mol.K
Total Enthalpy: 143.414 kcal/mol
Total Entropy: 112.447 cal/mol.K
I have also performed a frequency, optimization, frequency calculation for this set as well, for me to have 2 imaginary frequencies at the result as well. Are there any suggestions for what I can do next to remove these imaginary frequencies?