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All results from a given calculation for Si3H8 (trisilane)

using model chemistry: QCISD/3-21G

19 10 17 12 22

States and conformations

State Conformation minimum conformation conformer description state description
1 1 yes C2V 1A1
Energy calculated at QCISD/3-21G
 hartrees
Energy at 0K-867.028796
Energy at 298.15K-867.036242
HF Energy-866.798132
Nuclear repulsion energy188.930506
The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.
Vibrational Frequencies calculated at QCISD/3-21G
Mode Number Symmetry Frequency
(cm-1)
Scaled Frequency
(cm-1)
IR Intensities
(km mol-1)
Raman Act
4/u)
Dep P Dep U
1 A1 2142 2076 119.03      
2 A1 2131 2065 4.05      
3 A1 2118 2053 71.05      
4 A1 928 899 74.67      
5 A1 899 872 0.01      
6 A1 862 836 196.40      
7 A1 558 541 9.37      
8 A1 351 341 0.17      
9 A1 101 97 1.31      
10 A2 2138 2073 0.00      
11 A2 920 892 0.00      
12 A2 708 686 0.00      
13 A2 432 419 0.00      
14 A2 79 77 0.00      
15 B1 2144 2078 212.75      
16 B1 2132 2066 1.42      
17 B1 924 896 81.04      
18 B1 585 567 10.67      
19 B1 299 290 19.15      
20 B1 92 89 0.00      
21 B2 2141 2075 56.42      
22 B2 2125 2060 102.77      
23 B2 922 894 35.93      
24 B2 852 826 299.83      
25 B2 704 683 276.27      
26 B2 448 434 24.02      
27 B2 410 397 1.28      

Unscaled Zero Point Vibrational Energy (zpe) 14072.8 cm-1
Scaled (by 0.9692) Zero Point Vibrational Energy (zpe) 13639.3 cm-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.
Rotational Constants (cm-1) from geometry optimized at QCISD/3-21G
ABC
0.28587 0.06470 0.05595

See section I.F.4 to change rotational constant units
Geometric Data calculated at QCISD/3-21G

Point Group is C2v

Cartesians (Å)
Atom x (Å) y (Å) z (Å)
Si1 0.000 0.000 0.944
Si2 0.000 1.961 -0.441
Si3 0.000 -1.961 -0.441
H4 1.231 0.000 1.821
H5 -1.231 0.000 1.821
H6 0.000 3.221 0.391
H7 0.000 -3.221 0.391
H8 1.226 1.946 -1.322
H9 -1.226 1.946 -1.322
H10 -1.226 -1.946 -1.322
H11 1.226 -1.946 -1.322

Atom - Atom Distances (Å)
  Si1 Si2 Si3 H4 H5 H6 H7 H8 H9 H10 H11
Si12.40132.40131.51111.51113.26773.26773.22873.22873.22873.2287
Si22.40133.92273.23693.23691.50945.24841.50971.50974.18864.1886
Si32.40133.92273.23693.23695.24841.50944.18864.18861.50971.5097
H41.51113.23693.23692.46203.73243.73243.69614.43834.43833.6961
H51.51113.23693.23692.46203.73243.73244.43833.69613.69614.4383
H63.26771.50945.24843.73243.73246.44122.46232.46235.57945.5794
H73.26775.24841.50943.73243.73246.44125.57945.57942.46232.4623
H83.22871.50974.18863.69614.43832.46235.57942.45224.59973.8916
H93.22871.50974.18864.43833.69612.46235.57942.45223.89164.5997
H103.22874.18861.50974.43833.69615.57942.46234.59973.89162.4522
H113.22874.18861.50973.69614.43835.57942.46233.89164.59972.4522

picture of trisilane state 1 conformation 1
More geometry information
Calculated Bond Angles
atom1 atom2 atom3 angle atom1 atom2 atom3 angle
S1 S2 H6 111.304 S1 S2 H8 109.156
S1 S2 H9 109.156 S1 S3 H7 111.304
S1 S3 H10 109.156 S1 S3 H11 109.156
S2 S1 S3 109.532 S2 S1 H4 109.548
S2 S1 H5 109.548 S3 S1 H4 109.548
S3 S1 H5 109.548 H4 S1 H5 109.104
H6 S2 H8 109.285 H6 S2 H9 109.285
H7 S3 H10 109.285 H7 S3 H11 109.285
H8 S2 H9 108.610 H10 S3 H11 108.610
Electronic energy levels
Charges, Dipole, Quadrupole and Polarizability